I made the same decision on my '63 roadster. I wanted basically a stock look, but wanted to protect my numbers matching investment. I took out the original 327 and put it in the corner, and installed a crate motor with a TPI unit. With the hood closed, the car looked completely stock. If you want, you can do the crate motor and continue the stock look to the motor with some attention to detail. At any rate, I put the engine aside for 7 years. I didnt have to put it back in the car to protect the value... when I sold it, the car was a beautiful stock looking driver, and I had the original numbers matching motor to go with it. It sold immediately for top dollar.

 

I was going to have my original 350 rebuilt. Fortunately a couple shops said they wouldn't touch it because of the amount of rust inside. (I guess Bubba didn't think he needed to use anti-freeze in Arizona or California.)

I ended up buying a slightly used GM 350 HO Deluxe crate with 1,200 miles on it - just broken in. That is a GREAT engine for an '80 with a couple hundred pounds less than original. I'm below that 10 lbs./HP mark.

 

Check out this 383 for $3100. Looks pretty good what do you think?
http://www.jegs.com/webapp/wcs/store...61056_-1_10763

 

It's interesting...but I think they're cutting corners in the wrong spots. They use a SCAT crank (good), but then 5.7" stock Chevy rods (bad IMHO). I think you can do better for about the same amount of money on your own...

 

Wouldn't a set of World Products "S/R Torquers", a Ohio Crankshaft $2500 all new, all forged 383 Shortblock (with the factory holes for a hydraulic roller), a set of junkyard roller lifters & pushrods, a used aluminium factory dual plane intake & a cam company's recommendation for a hydraulic roller get him there & still look real stock?

 

The S/R (Stock Replacement) heads are basically upgraded versions of the '462 "camel hump" heads - the Vortecs will outflow these across the board - but I agree that any aftermarket iron head is a reasonable choice.

Can't imagine needing all forged in this application; cast cranks are good to ~450 HP. GMPP sells their 383 forged shortblock for around $3500 - that'd make this a pretty pricey engine by the time we get everything else in place

Why take a $3500 forged shortblock and put junkyard lifters in?

I'm in complete agreement that an all iron 383 stroker with a hydraulic roller is the best of all worlds - just not the combination noted.

As a side note, the new bare blocks GMPP now sells have the bosses for the stock "spider" for the factory roller hydraulics. For $700, you get a NEW block with "production" tolerances - close enough for engines making < 1.2 HP/CID.

 

First of all I appreciate all the ideas. They really help as I work through the pro's and con's.

billla, your right........... It won't be stock and it won't perform. Then I have nothing and can't go back. SO I need to protect the original parts.

So I guess I don't want to modify the original stock heads and block.

I see 3 options:

option-1
Rebuild the engine to the original 350 hp spec and change out the transmission to gain the supposedly 30% more torque with a 5 or 6 speed.
The heads have 1.940/1.50 valves. Have been sitting 20 years but are not rusty. I assume they need to be rebuilt.
I believe the cast crank on the engine is good.
The cylinder bores will clean up with a .030 over. I say this with confidence because they look like all they really need is honing.
Definitely a large journal crank and block.
The original had domed pistons with a 11:1 Cr. I hear over 10:1 is a no no with todays gas. Maybe flat pistons to get down to to 10:1. Whats 10:1 going to do to my power?
Maybe I could go with a slightly more aggressive cam to make up for the CR? I have to buy the cam anyway. (I am told the Crane replacement is 967601.)

Option-2- Most HP with unmodified heads and block and change out the transmission.
Stroker 383 with original heads and block? Will this work? What HP?
Have heads rebuilt to original, 1.940 / 1.5 valves.
New rotating assembly with stroker crankshaft. Go cast as HP would probably be at or under 400hp?
New cam.
My reasoning is that the only other item I would have to buy other than option-1 is a crank so cost would be about the same and would be stock on the outside.
(Not sure if the above conditions require a different intake and carb.)


Option-3 Buy a crate engine and transmission then toss my block, crank and heads in the back of the garage! Again though, that means some day I have to rebuild the original engine which means more money.


I keep including a trans because it sounds like a big improvement and I assume I can change it back to the Muncie in a weekend.

Ok were narrowing down the scope. Can't wait to hear your thoughts.

 

Option 1
A good performance rebuild of your 327 will cost around $2000 max and should generate about 275HP at the flywheel with stock exhaust manifolds, around 300HP with 1-5/8 headers and a good exhaust. This is based on a good hyperutectic piston giving about 9.5:1 and a cam in the .430 lift range. CompCams makes the 327/350 spec cam (GM 3863151) under grind #12-106-3, but it's not the best cam for this application IMHO.

Option 2
I think this is your best choice, but it's important to recognize that the heads are the limiting factor, and we have to match the power level from the 383 to what the heads can deliver. Figure on about $3500 for this overhaul with a good cast crank/hyperutectic piston kit from Eagle or SCAT. Figure on 310HP or 340HP or so with headers, but a significant improvement in torque that will deliver a significant "seat of the pants" improvement. Again, the heads are the limitation here; they were holding us back at 327 CID and they'll be holding us back even more with more displacement. IMHO you could open up the valves to 2.02 and 1.6 without impacing the originality, as the same castings came with both sizes of valves. Maybe a little pocket porting and matching could get the HP up around 360 or so with headers. It's also important to note that you will need to notch the block for the stroker crank - it's not a big deal, but I didn't want to skip it given the focus on orginality.

Option 3
The sky's the limit here Note that you can still have a VERY factory looking engine, but really the power here is up to your budget.

 

Option-1 commet: So all things being equal the change in CR will reduce my HP by 75!! Or were the GM numbers at the time more wishful thinking?
Option-2 comment:
So around 310-340 HP with 1.94/1.50.
360 hp with 2.02 and 1.6
400+ with different heads?
All using the same cam? The reason I ask is if the set up works with both heads then I can start with the old heads, make sure they work and if it isn't enough I can buy some modern ones and won't have to change anything else. Good idea? What would modern heads cost?

 

All using the same cam? The reason I ask is if the set up works with both heads then I can start with the old heads, make sure they work and if it isn't enough I can buy some modern ones and won't have to change anything else. Good idea? What would modern heads cost?[/QUOTE]


Option 1: GM numbers were based on engine only on the dyno - so they're a bit optimistic in any case but the drop from 11:1 to 9.5 is significant and probably 1/2 of that drop

Option 2: Making 1HP+/CID is fairly easy with the right combo; 400-425 is very possible with the right heads and cam.

The cam is matched to the head, so if you invested in new heads you'd want to do a cam swap...which is not a big deal at all. But yes, you could absolutely build a solid 383 bottom end and do a top-end swap later - it's done all the time

Probably re-opening a big can of worms with the question around heads. Bottom line is they cost as much as you want to spend - $300 for a set of stock GMPP Vortecs to $750+ for an RHS head - and more if we start looking at aluminum heads. Just for fun, search for heads on Summit Racing or JEGS and look at some of the prices If you want to make 400HP+, we're looking at a 195-215cc runner head with 2.05/1.60 valves and probably around $600 each complete (iron).

We're kind of getting into another discussion here - at this point you're honing in on a plan, which is great, but it means that you need to pick the cam based on usage and budget, pick the heads based on the cam, and build the engine around these two. I think with some help from the folks here you can start getting a good plan together; the key is to MATCH the parts - budget tells you what you can achive, planning tells you how to get there with as few missteps as possible.

I'll shut up for a bit so someone else can chime in

 

IMHO i read u are new to engine rebuilding and the room for mistakes that ruin the whole effort is great. Just follow that overhaul book (i prefer the D. Vizard book myself) and install a hotter cam with your own heads and maybe some pocket porting (if u find a machine shop u trust). What i'm saying is rebuilding an eng is tough enough for the first time but a stroker motor with fancy heads is a big learning curve and can easy end up as junk.
If u try a stroker crank u are into clearancing the rods/crank and get ready for a headache trying to select pistons to match heads for good compression and a correct cam too. If you have never been there before it will be easy to make mistakes and waste a lot of good money. I read all the time of enthusiestes complaining they can't get the c.r. correct for the pistions they bought to match the big $$$ heads they spent on to make the big azz cam work they installed. And most can't even get there vacuum advance to work let alone the mechanical timing curve and tune the carb.
Heck u can buy guarenteed rebuildble 350" eng cores at most pick your own yards for 'bout $200. If u want 400hp the first time try it with second hand/new or used parts from ebay, swapmeets, trader mags, etc. U can build a good 400hp strokermotor the first try but i will take a lot of patience and time. But the questions u ask here are basic and it sounds like u will get in over your head building a fancy parts stroker. My .02 is just improve the eng u got or shop for a training eng in parts. I don't want to patronize u just save u $$$ and headaches here with your first engine build. But i think every vette enthusiest should rebuild an engine or build a high po motor for his own car and experience.
I have been following this post wanting to respond when i got the time and enjoy reading other eng building efforts as i learn from them to and find some of my own previous mistakes.
BTW that muncie trans is plenty strong and your 3.70 rear gear set is good all around ratio for performance on the street and hwy.: :


Hope this helps,
cardo0

 

cardo0
This sounds like great advice also. You are being very conservative because you don't know much about me. I like that. That is the responsible approach to take with people because they can listen to you guys and get in way over their head when trying to actually do the work. I guess I can too but a little background is in order. I am mechanically inclined. I have repaired my cars as a kid growing up; tune-ups, brakes, wheel bearings, springs, shocks,front end,, collision damage, body work, painting, etc, etc. I have worked on boats, jet skis, snowmobiles. I built a full size 2 seat airplane from plans, not a kit, over an 8 year period of time and flew it! I can do any home improvement stuff, electrical, plumbing, carpentry. Big stuff like room additions, bath and kitchen gut jobs, etc.
I am very confident in repairing or replacing anything on my 68.

BUT, I NEVER CRACKED OPEN A V8!

So I know enough to know a person can get in trouble. The parts MUST be compatible, tolerances must be respected. I also don't want to build something I have to be fiddling with all the time. I want to enjoy building it and then drive it. I don't want to be always playing around with it. While it won't be a daily driver, I want a reliable engine with a reasonable idle that will not risk my numbers matching block and heads status.

 

I'm going to think about these comments a day or 2. Then I will get back to you guys.
I really appreciate the help. Seems like good, reliable, realistic advice.

Alan

 

I appreciate all the advice. Hers what I think I want to do.

I build a 383 stroker emphasizing acceleration from a standing start for playing around town.
Use my existing heads modified to 2.02/1.6
Get a cam to match these heads.
Headers.
Hope for 360 hp.
This way my car looks completely stock.

If I am not satisfied with the performance I can either build up another engine or pull this motor and put in another cam and modern heads/carb/intake and get over 400hp.

Here is my my current train of thought.

I have to have the original heads rebuilt anyway so I will use them and see if I like the power.

A cam change later doesn't require messing with the bottom end.

Modifying the block for the stroker only requires machining a little clearance. I wouldn't be doing it because It would be done at the machine shop when they bore to .030 and deck the top.

Because there is no real change to the block I could go back to a 327 engine if I really had to!

A 400hp to 425hp stroker sounds relatively conservative so the right answers for what components to use should be available and agreeable.

One I have the right parts and the machining is done, I will follow the same steps rebuilding, just as if it were a 327.

I don't think building up the 327 would make me any smarter when it comes to picking out matching parts for a future 383.


Questions:
Is a 383 always a stroker or is there a factory 383?

Iron vs Aluminum heads. I assume aluminum is not a performance gain, only weight and maybe looks? One could argue theres a gain in performance due to saving some weight.

What is the "runner" referred to a spec on the heads that I keep seeing in the catalogs and was mentioned here?

For better or for worse will the 383 make my engine sound different?

When changing a cam, can't the bearings fall out when sliding it in?
Would you know if they did?
Maybe you remove the oil pan and make sure everything is ok?

Changing cam doesn't require pulling bottom end apart, right?

Great comments on the trans! if it's strong enough maybe all I have to do is change gears in trans and rear end.

I hear a 10:1 ratio between engine and tires is ideal for 1st gear get up and go?

I guess it depends on the torque curve of the engine. If higher RPM gets you in a much better curve, then you want a higher gear ratio to get you into the good part of the curve, right?

So to get the engine to tire ratio you multiply trans 1st gear ratio by rear end ratio, right?


Can't wait to hear your responses!!!!!!!!

Alan

 

This sounds like a great compromise approach IMHO and I think you'll be very happy with the results

• There is a GMPP crate 383 (4.00 x 3.80) but no "factory" 383s.
• The iron v. aluminum debate is huge, but recent testing has caused me to believe that there are no benefits other than ease or porting and weight. Anecdotal evidence was that aluminum heads allowed higher CR due to better heat transfer from the chamber, but IMHO this has not been supported by recent back-to-back dyno tests with identical CNC heads in iron and aluminum. Many will disagree
• The runner is the intake runner volume. There's another thread on this around here, but bottom line is that bigger ports flow more (obvious) but give up low-speed driveability due to low intake velocity at low RPM. 180-220 heads are as far as you want to go on something you'd consider a daily driver. Camel hump heads are around 175cc depending on the casting.
• I honestly can't say on the sound difference.
• Cam bearings are pressed into the block. Done many, MANY cam swaps with no bearing problems
• It doesn't require anything on the bottom end. Note that you do need to drop the pan slightly to get the timing cover off - a 2-piece cover would make this far easier.

 

billla, thanks for the quick response. You have helped tremendously and everything you have said makes sense and is reasonable.

I would appreciate other opinions. Even if you agree because it helps to confirm the current thinking.

 

Ok, I have been pricing things and I can't find a 327-383 rotating assembly or just a crank from either Scat or Eagle or anyone else for that matter. They all say 350.
My assumption is that the only difference between a stock 327 and 350 is the stroke. So since I may be going to a 383 doesn't matter and even though they all say 350 it works just the same in my 327?
But I could be wrong because why do they only say 350? They should say 327/350. Maybe the 350 is just more popular.
Please confirm.

Also does that apply to gasket kits too?


Other subject:
Anyone else going to give their opinions on the track I have been going down in the threads? Looking for a confirmation or CONSTRUCTIVE criticism.

 

Alan,

To change the internals of the block you should have a machinist who consistently builds these engines to help you. I don't know of how the 327/383 interaction would go based on the difference of castings or whatever. Remember any 383 crank builder will assume (and take it for granted) that you would only use a 4 bolt 350 block casting to start with. Using an original block, 2 bolt, will seem a bit unusual to him. With a little understanding he will help you fit what you need together. My builder out here I can ask next week...

Off to RENO for the races...!

I should be installing my motor next week...

 

International,
Thanks for the input. You input is valuable as you have proven to be quite knowledgeable with great logic. I would appreciate getting input from your builder. I now have 4 recommended machine shops and will start asking questions.
I guess I am starting to have some concerns that a 327 stroker is a little unusual. If that is not the case I need to understand that. I don't want to do anything that will risk this block.
Maybe I have to go forged and modify to 4 bolt to be real safe. Thats an extra grand for forged. Maybe it's overkill?

I thought I was learning that internally the difference between a 327 and a 350 block is the 4 bolt and the stroke. In other words a 350 crank would fit in a 327 block. If that's not true then where are the 327 to 388 stroker kits? I don't see them. Need a little help here.

Have fun at Reno. I always thought it would be cool to see the air races.

 

2 of the 383 stroker kits that Scat sells are exactly the same except for the rods. 1-90350 uses 5.700 inch rods and 1-90500 uses 6.000 inch rods.

3-questions:
1) How can they BOTH produce 383 CID and a compression ratio of 9.8 when there is a whole .300 inch difference in rods. To me that means there is .300 inch difference where the piston is located in the cylinder at TDC. Only thing I can think of is that the hypereutectic dish pistons are different models. Meaning that maybe the centerline of the pin to the top of the piston is different, by .300.

2) What are the factors to consider when deciding 5.700 vs. 6.000. I know billla says 5.700. Is it about inertia and how fast the engine revs?

3)Scat sells 407 rotating assemblies using a 400 crank. Heck why not go with that and get 407 CID? Maybe stock heads with 2.02 valves limit me to 383.