Just bore the block??????
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
Found a shop close so will take it up there next week and they can pull the engine/etc... This should give me some time to research and see what my options are. Might be a good time to upgrade to a MSD ignition setup too. Should probably change out the fuel pump while I'm at it.
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
Nowadays, virtually all crate motors have a one-piece rear main seal (GM changed from two-piece to one-piece '86-'87); their flexplates & flywheels have different bolt patterns and are not interchangeable. You'll need a New flexplate. New flexplate can be had for < $40. GM crate I suggest below has Forged Steel crankshaft and is the newer One-piece RMS design which has a smaller bolt circle than your Two-piece RMS motor has.
Be advised. All GM sbc crates are completely brand new top to bottom. And have the best warranty in the business with No Restriction on where you Must file any claim (sue) if you can't resolve a warranty issue.
Be advised. Crates from either ATK (aka Vege) and BPE have a warranty which Restricts user to file (sue) in Company's State of choice; ATK/Vege = Illinois while BPE = Nebraska. Suggest read the fine print and/or consult Your counselor Before writing the check; because, sadly, sometimes stuff happens.
The BPE motor referenced above has a New block but many (if not most) BPE crates use a remanufactured block which has been bored out to (or beyond) blocks' intended/practical limit.
ATK/Vege crates are similar; some have new blocks while some use a remanufactured block which has been bored out to (or beyond) blocks' intended/practical limit.
When it comes to cranks: Cast Steel is Not Forged Steel. Cast is Cast. Forged is Forged; and is more robust than Cast.
FWIW, GM sells a True 383" (the one you reference) with standard 4 inch bore & 3.800" stroke forged crank.
This $3600 motor: from GM
https://www.gmperformancemotor.com/parts/12691673.html
This roller motor will easily make 300-315 Gross SAE HP on an engine dyno with a good carb & distributor & headers
With a drop-in spring & retainer swap ($140),bigger roller cam swap ($250) it'll easily make ~ 425 Gross SAE HP on an engine dyno; and do it reliably.
Freshen your carb & dist, a new Vortec intake $175 ...DIY I'm seeing under $5K. Cam & spring swap rather easy.
four USA-made billet steel roller cams for sbc
https://www.summitracing.com/search/...rder=Ascending
think long & hard
Be advised. All GM sbc crates are completely brand new top to bottom. And have the best warranty in the business with No Restriction on where you Must file any claim (sue) if you can't resolve a warranty issue.
Be advised. Crates from either ATK (aka Vege) and BPE have a warranty which Restricts user to file (sue) in Company's State of choice; ATK/Vege = Illinois while BPE = Nebraska. Suggest read the fine print and/or consult Your counselor Before writing the check; because, sadly, sometimes stuff happens.
The BPE motor referenced above has a New block but many (if not most) BPE crates use a remanufactured block which has been bored out to (or beyond) blocks' intended/practical limit.
ATK/Vege crates are similar; some have new blocks while some use a remanufactured block which has been bored out to (or beyond) blocks' intended/practical limit.
When it comes to cranks: Cast Steel is Not Forged Steel. Cast is Cast. Forged is Forged; and is more robust than Cast.
FWIW, GM sells a True 383" (the one you reference) with standard 4 inch bore & 3.800" stroke forged crank.
This $3600 motor: from GM
https://www.gmperformancemotor.com/parts/12691673.html
This roller motor will easily make 300-315 Gross SAE HP on an engine dyno with a good carb & distributor & headers
With a drop-in spring & retainer swap ($140),bigger roller cam swap ($250) it'll easily make ~ 425 Gross SAE HP on an engine dyno; and do it reliably.
Freshen your carb & dist, a new Vortec intake $175 ...DIY I'm seeing under $5K. Cam & spring swap rather easy.
four USA-made billet steel roller cams for sbc
https://www.summitracing.com/search/...rder=Ascending
think long & hard
If I have to bump the budget up a bit to cover a few things that is fine.... I still have the stock trans so maybe swap that out next year once I feel out the engine...
Last edited by onaqwst; Oct 5, 2021 at 12:25 AM.
Pro
Joined: Jul 2021
Posts: 719
Likes: 156
OP
? What year and which model is your C3? Please state now and in any future thread. Lotsa wasteful guessing here from not knowing that.
If it's a 75 thru 80 it came OE with desirable 4-pin GM HEI distributor. If that's what yours has, there's No need to buy DUI or MSD etc; just freshen Your 4-pin HEI.
Same goes for carb, if it's 80 or older, it came OE with desirable Rochester QuadraJet; If that's what yours has; just freshen Your QJet.
? What year and which model is your C3? Please state now and in any future thread. Lotsa wasteful guessing here from not knowing that.
If it's a 75 thru 80 it came OE with desirable 4-pin GM HEI distributor. If that's what yours has, there's No need to buy DUI or MSD etc; just freshen Your 4-pin HEI.
Same goes for carb, if it's 80 or older, it came OE with desirable Rochester QuadraJet; If that's what yours has; just freshen Your QJet.
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Ditto on a simple HEI will get the job done.
Todays aftermarket heads will outperform most ported factory heads plus they have an advanced chamber design to preventpinging and are just efficient period. Sell the old ones off and step up lotsa power in heads today.
3600 is a steal for a brand new everything (block too) roller cam 383. Managed to spend 18k on mine and its outdated
Todays aftermarket heads will outperform most ported factory heads plus they have an advanced chamber design to preventpinging and are just efficient period. Sell the old ones off and step up lotsa power in heads today.
3600 is a steal for a brand new everything (block too) roller cam 383. Managed to spend 18k on mine and its outdated
Last edited by cv67; Oct 5, 2021 at 12:30 PM.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Agree with above. You wasted money having those boat anchors ported. And that’s the reason you don’t have any power. Your bottom end might even be fine. you don’t know.
Last edited by derekderek; Oct 6, 2021 at 07:13 AM.
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
OP
? What year and which model is your C3? Please state now and in any future thread. Lotsa wasteful guessing here from not knowing that.
If it's a 75 thru 80 it came OE with desirable 4-pin GM HEI distributor. If that's what yours has, there's No need to buy DUI or MSD etc; just freshen Your 4-pin HEI.
Same goes for carb, if it's 80 or older, it came OE with desirable Rochester QuadraJet; If that's what yours has; just freshen Your QJet.
? What year and which model is your C3? Please state now and in any future thread. Lotsa wasteful guessing here from not knowing that.
If it's a 75 thru 80 it came OE with desirable 4-pin GM HEI distributor. If that's what yours has, there's No need to buy DUI or MSD etc; just freshen Your 4-pin HEI.
Same goes for carb, if it's 80 or older, it came OE with desirable Rochester QuadraJet; If that's what yours has; just freshen Your QJet.
Pro
Joined: Jul 2021
Posts: 719
Likes: 156
Ditto on a simple HEI will get the job done.
Todays aftermarket heads will outperform most ported factory heads plus they have an advanced chamber design to preventpinging and are just efficient period. Sell the old ones off and step up lotsa power in heads today.
3600 is a steal for a brand new everything (block too) roller cam 383. Managed to spend 18k on mine and its outdated
Todays aftermarket heads will outperform most ported factory heads plus they have an advanced chamber design to preventpinging and are just efficient period. Sell the old ones off and step up lotsa power in heads today.
3600 is a steal for a brand new everything (block too) roller cam 383. Managed to spend 18k on mine and its outdated
https://www.gmperformancemotor.com/parts/12691673.html
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Melting Slicks
Joined: Jun 2014
Posts: 2,226
Likes: 497
From: NJ
How many miles on the engine? And is it a numbers matching car? And if you want to know for sure if your engine is just worn out, and needs rebuilding, have a leak down test performed on the engine. This will tell you the overall condition of the engine. Go from there.
Team Owner
Joined: Jan 2007
Posts: 53,648
Likes: 878
From: Southern Cal Ca
St. Jude Donor '22
Maybe I need to get a full part list so I can order soon and make this a winter project...... maybe get my dad involved to have him do something (he's retired) and spark his mechanical brain again... I buy parts, he helps build it.... then I'll pull the motor in the garage and see what happens....
If I have to bump the budget up a bit to cover a few things that is fine.... I still have the stock trans so maybe swap that out next year once I feel out the engine...
If I have to bump the budget up a bit to cover a few things that is fine.... I still have the stock trans so maybe swap that out next year once I feel out the engine...
https://www.gmperformancemotor.com/parts/19418654.html
You can put anything you want on top.
No need to pull the engine again.
Use your original heads and mani, carb etc.
Slowly add higher and high performance parts as money allows.
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
Decisions and time.. a lot of good options thus far. I could do the 383 base since I have a mild cam (no clue on specs) and maybe buy some better heads.... 650 holley DP might have to be upgraded?... could be a good winter project
Pro
Joined: Jul 2021
Posts: 719
Likes: 156
JMO
HT383E ... it IS a truck motor & Not such a great choice for a performance car. That's a good motor but a hogtied combo for a performance car. Look at your specs ... it has a baby cam (both motorboat & truck) ... makes tons of torque but puny horsepower (truck motor). Also has a pricey Long reverse rotation water pump w/ threaded snout to fit GM threaded clutch fan (truck motor) ... you won't use that pump and you won't use its pricey distributor unless you also use a truck ECM & injection.
that partial is a poor value ... NO cam or roller lifters nor the dog bones & spider either & no heads ... poor value at ~ $4300
In general, vettes & Long pumps don't fit. Use a pump Like what's on yours now because it'll fit Your brackets & pulleys; any other type pump won't fit.
best value & bang for buck & potential for more giddyup is that $3600 L31 replacement ... the very reasons I suggested it in the first place.
YMMV
HT383E ... it IS a truck motor & Not such a great choice for a performance car. That's a good motor but a hogtied combo for a performance car. Look at your specs ... it has a baby cam (both motorboat & truck) ... makes tons of torque but puny horsepower (truck motor). Also has a pricey Long reverse rotation water pump w/ threaded snout to fit GM threaded clutch fan (truck motor) ... you won't use that pump and you won't use its pricey distributor unless you also use a truck ECM & injection.
that partial is a poor value ... NO cam or roller lifters nor the dog bones & spider either & no heads ... poor value at ~ $4300
In general, vettes & Long pumps don't fit. Use a pump Like what's on yours now because it'll fit Your brackets & pulleys; any other type pump won't fit.
best value & bang for buck & potential for more giddyup is that $3600 L31 replacement ... the very reasons I suggested it in the first place.
YMMV
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
JMO
HT383E ... it IS a truck motor & Not such a great choice for a performance car. That's a good motor but a hogtied combo for a performance car. Look at your specs ... it has a baby cam (both motorboat & truck) ... makes tons of torque but puny horsepower (truck motor). Also has a pricey Long reverse rotation water pump w/ threaded snout to fit GM threaded clutch fan (truck motor) ... you won't use that pump and you won't use its pricey distributor unless you also use a truck ECM & injection.
that partial is a poor value ... NO cam or roller lifters nor the dog bones & spider either & no heads ... poor value at ~ $4300
In general, vettes & Long pumps don't fit. Use a pump Like what's on yours now because it'll fit Your brackets & pulleys; any other type pump won't fit.
best value & bang for buck & potential for more giddyup is that $3600 L31 replacement ... the very reasons I suggested it in the first place.
YMMV
HT383E ... it IS a truck motor & Not such a great choice for a performance car. That's a good motor but a hogtied combo for a performance car. Look at your specs ... it has a baby cam (both motorboat & truck) ... makes tons of torque but puny horsepower (truck motor). Also has a pricey Long reverse rotation water pump w/ threaded snout to fit GM threaded clutch fan (truck motor) ... you won't use that pump and you won't use its pricey distributor unless you also use a truck ECM & injection.
that partial is a poor value ... NO cam or roller lifters nor the dog bones & spider either & no heads ... poor value at ~ $4300
In general, vettes & Long pumps don't fit. Use a pump Like what's on yours now because it'll fit Your brackets & pulleys; any other type pump won't fit.
best value & bang for buck & potential for more giddyup is that $3600 L31 replacement ... the very reasons I suggested it in the first place.
YMMV
current situation.. nothing fancy...
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
Yup, ...but GM 12691673 is a Vortec head roller 350 w/ forged crank ... not 383 ... regardless, $3600 is a great value!
https://www.gmperformancemotor.com/parts/12691673.html
https://www.gmperformancemotor.com/parts/12691673.html
thinking about purchasing it this weekend. need to just make it happen at this point. vette isn't going anywhere so mine as well get this project moving... I was thinking of just dropping a few more bucks and doing a full dressed motor, but will crunch number the next few days... I think 7-8k would be my max at this point if it was an easy swap....just dont want to regret it later of not maxing out a SB to a decent performance setup.
https://blueprintengines.com/product...tor-bp4002ctc1
https://blueprintengines.com/product...on-bp35513ctf1
Last edited by onaqwst; Oct 6, 2021 at 05:15 PM.
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
you think?.... my knowledge on engines is like 1/10... powertools/fabrication is 15/10..hahah.... need to make sure my stock auto trans and diff will be fine... you know... can't replace everything..ahha
Old Pro Solo Guy
Joined: Dec 2017
Posts: 8,035
Likes: 4,389
From: Marlton NJ
What rear gear and trans do you have?
I ask because the bigger engine with more torque will much more easily accomodate a mild torque convertor and mild rear gear, and still run great. A smaller engine needs those two items much more optimized to keep up.
I ask because the bigger engine with more torque will much more easily accomodate a mild torque convertor and mild rear gear, and still run great. A smaller engine needs those two items much more optimized to keep up.
Thread Starter
Le Mans Master
Joined: Nov 2004
Posts: 7,186
Likes: 45
From: detroit area
stock for 1977 (auto). I have not touched these when I tore it all down years ago....
Safety Car
Joined: May 2001
Posts: 4,749
Likes: 1,642
From: Fairfax Virginia
That is true as I tried ordering a Camshaft from Competition Cams on and they said "most wouldn't work with a 3.36 rear" axle ratio. The Tech support said I would need a 3.60 or higher rear axle. It really limited the choices of a cam for a 427 with a 3.36 rear.
My C3 was delivered with the "economy" 3.36 rear ratio and the four speed it has and is great at getting "Good" mileage even with a Double Pumper on top. Our Corvette club went on a ride one time and I drove from my Home in Virginia about 35 miles to meet them and then 60 plus miles on to a state park. I watched several of my buddies with the 4.11 rears getting gas on the way home. I drove a 427 at 70 plus most of the day and I got home with a bit over 1/4 tank.
Having the right combination makes a huge difference. I like the mileage as gasoline is not cheap like it had been.
My C3 was delivered with the "economy" 3.36 rear ratio and the four speed it has and is great at getting "Good" mileage even with a Double Pumper on top. Our Corvette club went on a ride one time and I drove from my Home in Virginia about 35 miles to meet them and then 60 plus miles on to a state park. I watched several of my buddies with the 4.11 rears getting gas on the way home. I drove a 427 at 70 plus most of the day and I got home with a bit over 1/4 tank.
Having the right combination makes a huge difference. I like the mileage as gasoline is not cheap like it had been.