383 Stroker - On a Budget?
07-28-2014, 01:12 AM
#21
Instructor
Understand where you're coming from.
Machine work could run $400 or so, but $300 is possible.
How thick of a head gasket do you want? What compression ratio? That's going to be kind of an issue with a stroker underneath 58cc heads. You could go with dished pistons, but then you might not have the quench you need.
It's highly likely your valve guides will need to be redone, in one way or another, and the valve seats might need some help as well. You won't know for sure until you pull some things apart. This can be expensive, and you can't do it at home.
New valves too?
It also looks like the $700 version of the stroker kit does not include connecting rods or balancing. That's more cost to consider. Could be $200-$300
You should probably get better head bolts and rod bolts as well. Not a good idea to reuse the stock bolts. $50 and up for that.
It does appear that the stroker kit comes with a cam, but I could see how you'd want something different. Not efficient to do it that way, but it happens. You'll want to call a cam place and ask them for a recommendation, and then use the springs, lifters, lube, and everything else that the specific cam requires.
Assembly stuff (lube, misc. tools, fluids, paint, etc.) will easily run another $200-$300.
You won't really know what pushrods you need until you mock up the engine. You might guess right, but it's better to buy once.
Will you need bigger injectors with this build? Higher fuel pressure? $$$
Will you want/need to replace any of the sensors (water temp. oil temp. knock)?
Your stock distributor might not work with the new cam (gear metals are different and not always compatible).
Plugs and wires?
How will your clutch look when you pull it off? It's a good time to replace a worn clutch, as you'll never have easier access. Will the stock clutch hold the extra torque of a 383?
I have the Corsa cat-back exhaust on my car, and I really like it. It's a good investment. Sounds good, looks good, makes just a little more power (not much).
You need to match the cam, to the port volume, to the compression ratio, to the intake runner length, the rocker ratio, to the gearing, to the (you get the point).
California is certainly not the easiest place to build a budget project car!
The cheapest way to get your hands really dirty and build your own stuff (with this car) would be to pick up someone's failed or stalled project off of craigslist, and go from there. Very low milage short blocks can often be found for under $500. Sometimes they haven't even put it together yet. That's better. Rebuild a Holley carb, throw on a low-rise dual plan manifold, and learn to tune the carb. Sell your stock heads (maybe $300), and invest in some decent 64cc aluminum heads that will work better on a 383. That could be almost as cheap as rebuilding the old heads.
A 383 with good heads, dual plain manifold, and well tuned carb can easily make 420+ torque. A very street friendly 450 hp/tq is not unreasonable with really good heads and the right cam/compression/carb tuning.
Fact is, with a good set of heads (like AFR, Profiler good) and a roller cam a 383 can be an absolute torque monster of an engine that also has a strong top end (with a carb). But, you will loose a HUGE amount of that power as soon as you bolt on the TPI intake and stock exhaust manifolds. The exhaust problem is easily fixed if you don't have visual emissions checks, but the intake problem sucks. It costs a lot of money to get a high horsepower fuel injection setup under the hood of a C4. Fuel injection is expensive anyway, and the hood clearance issues make it harder.
I guess you could always throw the TPI and stock exhaust back on for inspection.
Good Luck! Let us know where you end up.
Machine work could run $400 or so, but $300 is possible.
How thick of a head gasket do you want? What compression ratio? That's going to be kind of an issue with a stroker underneath 58cc heads. You could go with dished pistons, but then you might not have the quench you need.
It's highly likely your valve guides will need to be redone, in one way or another, and the valve seats might need some help as well. You won't know for sure until you pull some things apart. This can be expensive, and you can't do it at home.
New valves too?
It also looks like the $700 version of the stroker kit does not include connecting rods or balancing. That's more cost to consider. Could be $200-$300
You should probably get better head bolts and rod bolts as well. Not a good idea to reuse the stock bolts. $50 and up for that.
It does appear that the stroker kit comes with a cam, but I could see how you'd want something different. Not efficient to do it that way, but it happens. You'll want to call a cam place and ask them for a recommendation, and then use the springs, lifters, lube, and everything else that the specific cam requires.
Assembly stuff (lube, misc. tools, fluids, paint, etc.) will easily run another $200-$300.
You won't really know what pushrods you need until you mock up the engine. You might guess right, but it's better to buy once.
Will you need bigger injectors with this build? Higher fuel pressure? $$$
Will you want/need to replace any of the sensors (water temp. oil temp. knock)?
Your stock distributor might not work with the new cam (gear metals are different and not always compatible).
Plugs and wires?
How will your clutch look when you pull it off? It's a good time to replace a worn clutch, as you'll never have easier access. Will the stock clutch hold the extra torque of a 383?
I have the Corsa cat-back exhaust on my car, and I really like it. It's a good investment. Sounds good, looks good, makes just a little more power (not much).
You need to match the cam, to the port volume, to the compression ratio, to the intake runner length, the rocker ratio, to the gearing, to the (you get the point).
California is certainly not the easiest place to build a budget project car!
The cheapest way to get your hands really dirty and build your own stuff (with this car) would be to pick up someone's failed or stalled project off of craigslist, and go from there. Very low milage short blocks can often be found for under $500. Sometimes they haven't even put it together yet. That's better. Rebuild a Holley carb, throw on a low-rise dual plan manifold, and learn to tune the carb. Sell your stock heads (maybe $300), and invest in some decent 64cc aluminum heads that will work better on a 383. That could be almost as cheap as rebuilding the old heads.
A 383 with good heads, dual plain manifold, and well tuned carb can easily make 420+ torque. A very street friendly 450 hp/tq is not unreasonable with really good heads and the right cam/compression/carb tuning.
Fact is, with a good set of heads (like AFR, Profiler good) and a roller cam a 383 can be an absolute torque monster of an engine that also has a strong top end (with a carb). But, you will loose a HUGE amount of that power as soon as you bolt on the TPI intake and stock exhaust manifolds. The exhaust problem is easily fixed if you don't have visual emissions checks, but the intake problem sucks. It costs a lot of money to get a high horsepower fuel injection setup under the hood of a C4. Fuel injection is expensive anyway, and the hood clearance issues make it harder.
I guess you could always throw the TPI and stock exhaust back on for inspection.
Good Luck! Let us know where you end up.
07-28-2014, 01:17 AM
#22
Drifting
Thread Starter
Tom,
I agree that buying from a reputable seller such as Summit would be a good idea. Are there any specific brands or kits you'd recommend? I have a manual, which would mean it would need a flywheel instead of a flexplate, right? Every kit I looked at on Summit had the flexplate.
STL94,
I understand the irony of the situation. To be honest, I've been rethinking the choice to spend $1000 on exhaust. However, my exhaust is rusty and it sounds like baffles are loose in the mufflers, so a replacement is needed. I don't want something I won't like, and I hear people nearly universally recommend Corsa. I don't want my car to have an obnoxiously loud drone at highway speeds, and Corsa is the only one I've heard of without drone.
I agree that buying from a reputable seller such as Summit would be a good idea. Are there any specific brands or kits you'd recommend? I have a manual, which would mean it would need a flywheel instead of a flexplate, right? Every kit I looked at on Summit had the flexplate.
STL94,
I understand the irony of the situation. To be honest, I've been rethinking the choice to spend $1000 on exhaust. However, my exhaust is rusty and it sounds like baffles are loose in the mufflers, so a replacement is needed. I don't want something I won't like, and I hear people nearly universally recommend Corsa. I don't want my car to have an obnoxiously loud drone at highway speeds, and Corsa is the only one I've heard of without drone.
07-28-2014, 01:57 AM
#23
Drifting
Thread Starter
MJFuss,
Thanks for taking the time to give me such a lengthy and informative response!
So it sounds like you are of the opinion that I couldn't stroke it for $2000?
The carb idea is interesting. I have a few questions though. Is it legal to put an old carbureted engine in a newer car? Would it get decent mileage? I must admit one of the attractive points of the C4 was its fuel economy. Also, why is it easier to make power with a carbureted engine? Lastly, how much would it cost to do that and make a comparable amount of torque to a stroked L98, say, 380?
EDIT: Hmm, just thought of something. I'm awfully attached to the nifty MPG calculator and all the gauges on the dash. I'm guessing those would stop working with a non-computerized engine?
Thanks for taking the time to give me such a lengthy and informative response!
So it sounds like you are of the opinion that I couldn't stroke it for $2000?
The carb idea is interesting. I have a few questions though. Is it legal to put an old carbureted engine in a newer car? Would it get decent mileage? I must admit one of the attractive points of the C4 was its fuel economy. Also, why is it easier to make power with a carbureted engine? Lastly, how much would it cost to do that and make a comparable amount of torque to a stroked L98, say, 380?
EDIT: Hmm, just thought of something. I'm awfully attached to the nifty MPG calculator and all the gauges on the dash. I'm guessing those would stop working with a non-computerized engine?
Last edited by C4ProjectCar; 07-28-2014 at 02:59 AM.
07-28-2014, 02:02 PM
#25
Team Owner
Pro Mechanic
Tom,
I agree that buying from a reputable seller such as Summit would be a good idea. Are there any specific brands or kits you'd recommend? I have a manual, which would mean it would need a flywheel instead of a flexplate, right? Every kit I looked at on Summit had the flexplate
I agree that buying from a reputable seller such as Summit would be a good idea. Are there any specific brands or kits you'd recommend? I have a manual, which would mean it would need a flywheel instead of a flexplate, right? Every kit I looked at on Summit had the flexplate
You're right; you need a flywheel rather than a flex plate. Your current flywheel is already "balanced" meaning it has a counterweight on it, for the 1 pc rear main seal crank that you have on your '90. That weight, however will not be right for the "383" crank. Get what ever kit you choose and take the flex plate -no one is going to provide a flywheel. Take your flywheel and the new flex plate to a machine shop, have them balance your old flywheel to match the new flexplate. Balance/flywheel problem solved.
MJFuss makes a good point about your clutch...it may be time to replace it, while it's apart.
I don't agree about the connecting rods; I'd reuse the stock rods and upgrade the hardware (bolts). <-that is based on the budget and goals as you have described them.
Finally, while I agree your heads may be worn (guides and seats), they're working now, right? I'd leave them alone, since/if your plan is to upgrade when $$ permits later. IMO, factory heads w/160k on them, if well maintained should be ready for another 140k of service...again this is b/c of your budget/goals, as I understand them.
Last edited by Tom400CFI; 07-28-2014 at 02:07 PM.
07-28-2014, 02:41 PM
#26
I already have 3.33 gears in it (it's a 6-speed if that is relevant). Mileage is somewhat important to me.
With 3.33 already, would new rear end gears really be a big upgrade?
What affect would new gears have on effective power (pretty sure this isn't the right term), mileage, and driving experience (wouldn't a higher rear end gear ratio mean less time between shifts?)?
With 3.33 already, would new rear end gears really be a big upgrade?
What affect would new gears have on effective power (pretty sure this isn't the right term), mileage, and driving experience (wouldn't a higher rear end gear ratio mean less time between shifts?)?
Tommy
07-28-2014, 03:06 PM
#27
Team Owner
Pro Mechanic
Tomomycourt is right. I saw you mention that you "already have 3.33 gears" earlier in the thread...at that time I assumed that you had an automatic trans, in which case, a 3.33 would be a fun gear. In a 6 speed however, it's not. My '92 has a 3.45 gear as stock equipment, and Tommycourt is right; a 3.73 would definitely wake the feel of the car up noticeably. OTOH, with a "383" and stock TPI, you wouldn't need any more gear than 3.33.In either case, both options would provide a more fun, faster FEELING experience; neither will actually improve performance (objective numbers) much, if at all.
07-28-2014, 03:23 PM
#28
Instructor
It's probably not legal to put a carb on an originally fuel injected motor in California, but most of the other modifications you're looking to make are not legal either.
An Edlebrock Performer manifold can be had for $50 used (perfectly good), and you can get a pretty good used Holley in need of a rebuild for $150. Rebuild kit about $50. New fuel pressure regulator-$50-100, new HEI distributor-$100 or less. All the other stuff like gaskets and hardware would probably run another $100. That's under $600.
Really good heads: (I like Pro-Filer) $500 to $1000 depending upon what deal you find.
Used low-milage 383 short block: $500 if you shop around.
A well matched cam kit: $300.
Other misc. stuff: $300.
You're looking at a 450 tq/hp motor for $3000. Been done lots of times.
Carbs can be tuned for fuel milage. Won't be as good as fuel injection, but if you're good at tuning, and can keep your foot out if it, it's very close.
An Edlebrock Performer manifold can be had for $50 used (perfectly good), and you can get a pretty good used Holley in need of a rebuild for $150. Rebuild kit about $50. New fuel pressure regulator-$50-100, new HEI distributor-$100 or less. All the other stuff like gaskets and hardware would probably run another $100. That's under $600.
Really good heads: (I like Pro-Filer) $500 to $1000 depending upon what deal you find.
Used low-milage 383 short block: $500 if you shop around.
A well matched cam kit: $300.
Other misc. stuff: $300.
You're looking at a 450 tq/hp motor for $3000. Been done lots of times.
Carbs can be tuned for fuel milage. Won't be as good as fuel injection, but if you're good at tuning, and can keep your foot out if it, it's very close.
07-28-2014, 03:23 PM
#29
Instructor
It's probably not legal to put a carb on an originally fuel injected motor in California, but most of the other modifications you're looking to make are not legal either.
An Edlebrock Performer manifold can be had for $50 used (perfectly good), and you can get a pretty good used Holley in need of a rebuild for $150. Rebuild kit about $50. New fuel pressure regulator-$50-100, new HEI distributor-$100 or less. All the other stuff like gaskets and hardware would probably run another $100. That's under $600.
Really good heads: (I like Pro-Filer) $500 to $1000 depending upon what deal you find.
Used low-milage 383 short block: $500 if you shop around.
A well matched cam kit: $300.
Other misc. stuff: $300.
You're looking at a 450 tq/hp motor for $3000. Been done lots of times.
Carbs can be tuned for fuel milage. Won't be as good as fuel injection, but if you're good at tuning, and can keep your foot out if it, it's very close.
An Edlebrock Performer manifold can be had for $50 used (perfectly good), and you can get a pretty good used Holley in need of a rebuild for $150. Rebuild kit about $50. New fuel pressure regulator-$50-100, new HEI distributor-$100 or less. All the other stuff like gaskets and hardware would probably run another $100. That's under $600.
Really good heads: (I like Pro-Filer) $500 to $1000 depending upon what deal you find.
Used low-milage 383 short block: $500 if you shop around.
A well matched cam kit: $300.
Other misc. stuff: $300.
You're looking at a 450 tq/hp motor for $3000. Been done lots of times.
Carbs can be tuned for fuel milage. Won't be as good as fuel injection, but if you're good at tuning, and can keep your foot out if it, it's very close.
07-28-2014, 03:29 PM
#30
Team Owner
Pro Mechanic
I'd say that discussions about carbs in this thread are pointless, for the OP.
07-29-2014, 10:36 AM
#31
Team Owner
Member Since: Oct 2004
Location: altered state
Posts: 81,242
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2,602 Posts
St. Jude Donor '05
Just do the shortblock you can always upgrade intakes etc later but at least you have the foundation to build off of
Just finished a stock base that outflowedanAccel I have here out of the box. Lots of work but it can be done. Used ASM runners cam in the 2teens etc it will be a burnout king and work fine with your 3.33s
Down the road you could stick an AFR head on it which are smog legal....a heavily ported Accel base will come close to keeping up if its done right. It doesnt have to be numerically perfect car will still run strong
slickfx3 adapted some LT1 Shorties (dougs brand has an EO #) from the LT1 to his 89 and passed the visual somehow. Did a clean job and made it look factory.
Guy hereby the name of Dyno Don I think makes some that look passable too where all your89 stuff hooks right up. Hes in Orange County I think
The motor wont see any real rpm so basic cast stuff will work fine just get a decent balance job.
Just finished a stock base that outflowedanAccel I have here out of the box. Lots of work but it can be done. Used ASM runners cam in the 2teens etc it will be a burnout king and work fine with your 3.33s
Down the road you could stick an AFR head on it which are smog legal....a heavily ported Accel base will come close to keeping up if its done right. It doesnt have to be numerically perfect car will still run strong
slickfx3 adapted some LT1 Shorties (dougs brand has an EO #) from the LT1 to his 89 and passed the visual somehow. Did a clean job and made it look factory.
Guy hereby the name of Dyno Don I think makes some that look passable too where all your89 stuff hooks right up. Hes in Orange County I think
The motor wont see any real rpm so basic cast stuff will work fine just get a decent balance job.
07-29-2014, 02:32 PM
#32
Instructor
The OP indicated that he intended to, at some point, upgrade to a FIRST intake and switch back to the OE TPI for inspection.
It seems to me, if one is swapping for inspections, one can swap what they want. A carb is, therefore, in play. The OP said he wanted more grunt power for cheap, and wanted to get his hands dirty and learn some wrenching. A carb is still the cheapest way to make power on a SBC, and it would certainly provide plenty of wrenching opportunities.
Also, I'm not as big of a fan of bigger gears in a manual trans car. I have an '89 M6 with 3.33, and I think it's really plenty for the street. The earlier '89s had 3.45s, and I tried one, but it makes first gear really sort. I think first gear is short enough on these cars with the power dropping off where it does.
In an automatic a gear swap makes a bigger difference, IMHO.
It seems to me, if one is swapping for inspections, one can swap what they want. A carb is, therefore, in play. The OP said he wanted more grunt power for cheap, and wanted to get his hands dirty and learn some wrenching. A carb is still the cheapest way to make power on a SBC, and it would certainly provide plenty of wrenching opportunities.
Also, I'm not as big of a fan of bigger gears in a manual trans car. I have an '89 M6 with 3.33, and I think it's really plenty for the street. The earlier '89s had 3.45s, and I tried one, but it makes first gear really sort. I think first gear is short enough on these cars with the power dropping off where it does.
In an automatic a gear swap makes a bigger difference, IMHO.
07-29-2014, 03:43 PM
#33
Drifting
Thread Starter
I've done some research, and while I appreciate the suggestion, I'm not sure a carbureted engine would be right for me. Same with rear end gears. While short-term costs are important, long-term gas costs come into the equation too. I also don't want the gauges on the dash to be nonfunctional - that sort of thing bugs me. I'm looking to gain experience with engine work, and swapping rear end gears doesn't fit the bill. But again, I appreciate the suggestion and agree it would be a cheap way to make the car more fun to drive.
As far as the FIRST intake goes, the hope is that I won't have to swap it for inspection. It looks similar enough to the stock intake that I've heard it often isn't noticed.
I'm making the following comments to specific people in reply to their posts, but I'd appreciate input from anyone, not just who I am addressing.
Tom,
For a stroker, how much would it cost to have my flywheel rebalanced?
You said I could reuse the stock rods. Most stroker kits come with new rods, right? Or do you think it would be better to buy all of the components of a stroker kit separately?
Cuisinartvette,
Is modifying the stock base to flow better (not sure of the term - flowing the base or porting it, or both?) something that someone without machinist equipment or skills could do?
Also, how much would LT1 ST headers cost and improve performance?
MJFuss,
Thanks for your input on higher gears in a manual. That's exactly what I was wondering.
As far as the FIRST intake goes, the hope is that I won't have to swap it for inspection. It looks similar enough to the stock intake that I've heard it often isn't noticed.
I'm making the following comments to specific people in reply to their posts, but I'd appreciate input from anyone, not just who I am addressing.
Tom,
For a stroker, how much would it cost to have my flywheel rebalanced?
You said I could reuse the stock rods. Most stroker kits come with new rods, right? Or do you think it would be better to buy all of the components of a stroker kit separately?
Cuisinartvette,
Is modifying the stock base to flow better (not sure of the term - flowing the base or porting it, or both?) something that someone without machinist equipment or skills could do?
Also, how much would LT1 ST headers cost and improve performance?
MJFuss,
Thanks for your input on higher gears in a manual. That's exactly what I was wondering.
07-29-2014, 04:44 PM
#34
Drifting
Thread Starter
I'd like to minimize the down-time on my car as much as possible, so I had the idea to assemble the stroked short block on an engine stand, then just swap it with the block in my engine. I found a 350 TPI with 125k miles off of a '92 Z28 Camaro with an engine stand for $400, which seems like a pretty good deal. 3 questions:
Is the motor off the Camaro similar enough to the L98 to do this?
Do you think this would be a bad idea?
Is there a cheaper or better, but not more expensive, way to do what I'd like to do?
EDIT:
Came across this block from summit. Would this be a better way to go?
http://www.summitracing.com/parts/su...0-30/overview/
Is the motor off the Camaro similar enough to the L98 to do this?
Do you think this would be a bad idea?
Is there a cheaper or better, but not more expensive, way to do what I'd like to do?
EDIT:
Came across this block from summit. Would this be a better way to go?
http://www.summitracing.com/parts/su...0-30/overview/
Last edited by C4ProjectCar; 07-29-2014 at 04:51 PM.
07-29-2014, 06:46 PM
#35
Team Owner
Member Since: Oct 2004
Location: altered state
Posts: 81,242
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St. Jude Donor '05
With a good head the shorties shold be noticeable. The factory manifolds are pretty puky . Ok for stock thats about it
On the carb it would be too much trouble to swap back and forth. everyone I know out here inc myself with a carb, once the motor reaches about 200 the fuel wants to percolate he will have problems wiht the idle dragging down, running funny hot starts etc.
I dont have a Vette anymore and the eng compartment and parts temps stay very cool, but soon as that gauge hits 190 it starts...stay moving for ahwile its fine. Our gas is garbage for carbs (why I keep some VP around)
The term youre looking for is porting. If youre a DIYer you can save some #. It will take you a long time to do it, not 1 day or anything but better than paying someone. May have some extra pieces/pointers to help you out with.
Anyone know if the FIRST has EGR on it?
OP wondering if you might wanna look around for a complete shorblock!?
In the long run youre saving money just dont buy any CL or ebay stuff
On the carb it would be too much trouble to swap back and forth. everyone I know out here inc myself with a carb, once the motor reaches about 200 the fuel wants to percolate he will have problems wiht the idle dragging down, running funny hot starts etc.
I dont have a Vette anymore and the eng compartment and parts temps stay very cool, but soon as that gauge hits 190 it starts...stay moving for ahwile its fine. Our gas is garbage for carbs (why I keep some VP around)
The term youre looking for is porting. If youre a DIYer you can save some #. It will take you a long time to do it, not 1 day or anything but better than paying someone. May have some extra pieces/pointers to help you out with.
Anyone know if the FIRST has EGR on it?
OP wondering if you might wanna look around for a complete shorblock!?
In the long run youre saving money just dont buy any CL or ebay stuff
07-29-2014, 09:34 PM
#36
Instructor
The short block swap sounds like a good plan. Just make sure you sort out the compression ratio before you actually do the swap.
I didn't think you'd have any interest in running a carb, just thought it was something you should think about, and it might be good to know if you get in a tough spot with the swap. Your gauges would still work just fine with the carb swap though. You'd keep the computer, and it would think it was still running the engine, but it wouldn't be. The only thing you'd lose is the MPG feature.
To cuisinartvette: you're definitely right about the fuel percolating. You have to run the engine a little cooler, then heat shield the carb a bit and it's not a problem.
In Vizard's book there is specific information about porting 113 heads (the stock heads on a '90). The TPI base can also be ported to good effect, and it would not be apparent from the outside.
Your stock exhaust manifolds can also be ported a little, and it will make a difference.
You can replace the OEM exhaust with an aftermarket version that has high-flow cats, and I believe it's California legal. That would help with the back-end bottle neck. Or, for a cheaper solution, you can gut the pre cats and get a good, modern-tech main cat. It will run just as clean once it's warmed up (cleaner, probably), and you'll significantly reduce the back pressure. Cheap power boost, and it will actually help MPG.
If you're looking for more displacement, you won't be disappointed with a 400, if you can find one to build. Not only does it have more cubic inches, the added bore diameter reduces cylinder valve shrouding. Better air flow.
I didn't think you'd have any interest in running a carb, just thought it was something you should think about, and it might be good to know if you get in a tough spot with the swap. Your gauges would still work just fine with the carb swap though. You'd keep the computer, and it would think it was still running the engine, but it wouldn't be. The only thing you'd lose is the MPG feature.
To cuisinartvette: you're definitely right about the fuel percolating. You have to run the engine a little cooler, then heat shield the carb a bit and it's not a problem.
In Vizard's book there is specific information about porting 113 heads (the stock heads on a '90). The TPI base can also be ported to good effect, and it would not be apparent from the outside.
Your stock exhaust manifolds can also be ported a little, and it will make a difference.
You can replace the OEM exhaust with an aftermarket version that has high-flow cats, and I believe it's California legal. That would help with the back-end bottle neck. Or, for a cheaper solution, you can gut the pre cats and get a good, modern-tech main cat. It will run just as clean once it's warmed up (cleaner, probably), and you'll significantly reduce the back pressure. Cheap power boost, and it will actually help MPG.
If you're looking for more displacement, you won't be disappointed with a 400, if you can find one to build. Not only does it have more cubic inches, the added bore diameter reduces cylinder valve shrouding. Better air flow.
07-29-2014, 10:09 PM
#37
Drifting
Thread Starter
With a good head the shorties shold be noticeable. The factory manifolds are pretty puky . Ok for stock thats about it
On the carb it would be too much trouble to swap back and forth. everyone I know out here inc myself with a carb, once the motor reaches about 200 the fuel wants to percolate he will have problems wiht the idle dragging down, running funny hot starts etc.
I dont have a Vette anymore and the eng compartment and parts temps stay very cool, but soon as that gauge hits 190 it starts...stay moving for ahwile its fine. Our gas is garbage for carbs (why I keep some VP around)
The term youre looking for is porting. If youre a DIYer you can save some #. It will take you a long time to do it, not 1 day or anything but better than paying someone. May have some extra pieces/pointers to help you out with.
Anyone know if the FIRST has EGR on it?
OP wondering if you might wanna look around for a complete shorblock!?
In the long run youre saving money just dont buy any CL or ebay stuff
On the carb it would be too much trouble to swap back and forth. everyone I know out here inc myself with a carb, once the motor reaches about 200 the fuel wants to percolate he will have problems wiht the idle dragging down, running funny hot starts etc.
I dont have a Vette anymore and the eng compartment and parts temps stay very cool, but soon as that gauge hits 190 it starts...stay moving for ahwile its fine. Our gas is garbage for carbs (why I keep some VP around)
The term youre looking for is porting. If youre a DIYer you can save some #. It will take you a long time to do it, not 1 day or anything but better than paying someone. May have some extra pieces/pointers to help you out with.
Anyone know if the FIRST has EGR on it?
OP wondering if you might wanna look around for a complete shorblock!?
In the long run youre saving money just dont buy any CL or ebay stuff
As far as a complete short block goes, how's this look?
http://www.ebay.com/itm/CHEVY-SBC-383-SHORT-BLOCK-NO-CAM-OR-LIFTERS-/171398518453?pt=Motors_Car_Truck_Parts_Accessories&hash=item27e825d6b5&vxp=mtrWhich is a nice segue into my next question:
Why do you say to stay away from Craigslist or Ebay? I'd heard that was a good way to save money on slightly used parts.
07-29-2014, 10:22 PM
#38
Drifting
Thread Starter
The short block swap sounds like a good plan. Just make sure you sort out the compression ratio before you actually do the swap.
I didn't think you'd have any interest in running a carb, just thought it was something you should think about, and it might be good to know if you get in a tough spot with the swap. Your gauges would still work just fine with the carb swap though. You'd keep the computer, and it would think it was still running the engine, but it wouldn't be. The only thing you'd lose is the MPG feature.
To cuisinartvette: you're definitely right about the fuel percolating. You have to run the engine a little cooler, then heat shield the carb a bit and it's not a problem.
In Vizard's book there is specific information about porting 113 heads (the stock heads on a '90). The TPI base can also be ported to good effect, and it would not be apparent from the outside.
Your stock exhaust manifolds can also be ported a little, and it will make a difference.
You can replace the OEM exhaust with an aftermarket version that has high-flow cats, and I believe it's California legal. That would help with the back-end bottle neck. Or, for a cheaper solution, you can gut the pre cats and get a good, modern-tech main cat. It will run just as clean once it's warmed up (cleaner, probably), and you'll significantly reduce the back pressure. Cheap power boost, and it will actually help MPG.
If you're looking for more displacement, you won't be disappointed with a 400, if you can find one to build. Not only does it have more cubic inches, the added bore diameter reduces cylinder valve shrouding. Better air flow.
I didn't think you'd have any interest in running a carb, just thought it was something you should think about, and it might be good to know if you get in a tough spot with the swap. Your gauges would still work just fine with the carb swap though. You'd keep the computer, and it would think it was still running the engine, but it wouldn't be. The only thing you'd lose is the MPG feature.
To cuisinartvette: you're definitely right about the fuel percolating. You have to run the engine a little cooler, then heat shield the carb a bit and it's not a problem.
In Vizard's book there is specific information about porting 113 heads (the stock heads on a '90). The TPI base can also be ported to good effect, and it would not be apparent from the outside.
Your stock exhaust manifolds can also be ported a little, and it will make a difference.
You can replace the OEM exhaust with an aftermarket version that has high-flow cats, and I believe it's California legal. That would help with the back-end bottle neck. Or, for a cheaper solution, you can gut the pre cats and get a good, modern-tech main cat. It will run just as clean once it's warmed up (cleaner, probably), and you'll significantly reduce the back pressure. Cheap power boost, and it will actually help MPG.
If you're looking for more displacement, you won't be disappointed with a 400, if you can find one to build. Not only does it have more cubic inches, the added bore diameter reduces cylinder valve shrouding. Better air flow.
Depending on how much I end up spending to stroke my engine, I plan to get a new catback system.
As a matter of fact, my car was originally purchased outside CA, which is I'm assuming why it doesn't have precats. It passed smog in CA a year ago, so I'm hoping it'll pass again without precats. If not, I'll have to add some. Can you buy precats just for looks without internals for cheaper?
As far as replacing a main cat, how much would that cost? I think I recall MagnaFlow having one for a couple hundred bucks? And I assume you mean a high flow cat?
Help me out here. Is a 400 an entirely new engine?
07-29-2014, 11:06 PM
#39
Instructor
Because your pistons will be going further down into the cylinders with a stroker, the ratio between the air volume with the piston at the very bottom of the stroke to the air volume when the piston is top dead center will change. I don't remember the exact stock compression ratio for '90, but it was around 10.5:1.
That's reasonable for an aluminum headed motor running premium fuel.
Just using a thicker gasket to reduce the compression ratio is not always a good idea, as it can reduce the 'quench' effect of air swirling in the combustion chamber, and actually make you more prone to detonation.
The other thing that effects the compression ratio (often just shortened to 'CR) is how far the piston is from being flush with the top of the block when it's at top dead center. It's different stock from what a lot of people do for rebuilds.
Small differences in gasket thickness and deck height add up to significant differences in CR. Get it wrong and you either lose power or have problems with detonation.
Also, the size of your cam can effect the dynamic CR, which is what really matters.
Gets complicated!
Your car came with pre cats. All 1990 Vettes did. Every year after '85 I think.
You can pull off the front Y and just break up the inside of the cats with a longish steel rod, dump it all out, and bolt the Y back on. That's gutting them. The pre cats are only functional on warm-up. After that they just get in the way of exhaust flow. So gutting them will have no effect on your emissions as once the car is warmed up. A new main (high-flow, yes) cat would just work a little better than the old one, and would flow better. Cleaner, more power, no downside. Your old cat is worth $75-$100 in scrap, depending on local prices.
A 400 is the big boy in the first Generation SBC family. It's a different block with larger cylinder bores and a longer stroke. The external dimensions and bore spacing, however, are exactly the same, so it's a bolt-in. Also, any old SBC heads will work just fine on it if you drill out a couple of tiny steam holes. In fact, when you build a stroker you are actually putting a 400 crank in a 350 block (over bored).
So, don't limit yourself to 383s, if you can find a good 400 to build on you'll have something even better. Torque, torque, and more torque! And, no emissions person would be able to tell by looking at it. It would be pretty hard for anyone to tell unless they knew exactly what to look for.
That's reasonable for an aluminum headed motor running premium fuel.
Just using a thicker gasket to reduce the compression ratio is not always a good idea, as it can reduce the 'quench' effect of air swirling in the combustion chamber, and actually make you more prone to detonation.
The other thing that effects the compression ratio (often just shortened to 'CR) is how far the piston is from being flush with the top of the block when it's at top dead center. It's different stock from what a lot of people do for rebuilds.
Small differences in gasket thickness and deck height add up to significant differences in CR. Get it wrong and you either lose power or have problems with detonation.
Also, the size of your cam can effect the dynamic CR, which is what really matters.
Gets complicated!
Your car came with pre cats. All 1990 Vettes did. Every year after '85 I think.
You can pull off the front Y and just break up the inside of the cats with a longish steel rod, dump it all out, and bolt the Y back on. That's gutting them. The pre cats are only functional on warm-up. After that they just get in the way of exhaust flow. So gutting them will have no effect on your emissions as once the car is warmed up. A new main (high-flow, yes) cat would just work a little better than the old one, and would flow better. Cleaner, more power, no downside. Your old cat is worth $75-$100 in scrap, depending on local prices.
A 400 is the big boy in the first Generation SBC family. It's a different block with larger cylinder bores and a longer stroke. The external dimensions and bore spacing, however, are exactly the same, so it's a bolt-in. Also, any old SBC heads will work just fine on it if you drill out a couple of tiny steam holes. In fact, when you build a stroker you are actually putting a 400 crank in a 350 block (over bored).
So, don't limit yourself to 383s, if you can find a good 400 to build on you'll have something even better. Torque, torque, and more torque! And, no emissions person would be able to tell by looking at it. It would be pretty hard for anyone to tell unless they knew exactly what to look for.
07-29-2014, 11:13 PM
#40
Drifting
Thread Starter
What compression ratio would you recommend for 89 octane gas? And which cam? Without taking compression into consideration, I was thinking about either the LPE 217 or the Comp 08-501-8.
So there's no way to save money by just buying the metal precat shell, and not wasting money on the part of the precat that you break out?
Would a regular MagnaFlow 1990 Corvette cat fit the bill for a main cat? EDIT: The previous owner recently replaced the cat. Is it likely that the one on there right now is high-flow?
Lastly, is a 400 block harder to find and/or more expensive?
So there's no way to save money by just buying the metal precat shell, and not wasting money on the part of the precat that you break out?
Would a regular MagnaFlow 1990 Corvette cat fit the bill for a main cat? EDIT: The previous owner recently replaced the cat. Is it likely that the one on there right now is high-flow?
Lastly, is a 400 block harder to find and/or more expensive?
Last edited by C4ProjectCar; 07-29-2014 at 11:15 PM.