Max HP from the stock block..
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Instructor
Joined: May 2005
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From: Layton, UT
Max HP from the stock block..
I have a 1980 corvette im getting ready to start building. Regarding the motor, it is the original L48. I am wondering what the max power you this block could typically handle. I want at least 400 HP out of the engine, so should i start brand new or could i reuse the original block. Any thought?
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From: South of giving a damn
St. Jude Donor '11, '17
Do whichever way you want, that block will easily handle 400hp. However I do agree that the crate will be the easier of the 2 options. The crate will probably cost about the same as a full rebuild on you current block. Just research the builder, there's a lot of nimrods selling engines.
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Instructor
Joined: May 2005
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From: Layton, UT
Ive always rebuilt motors myself under the impression that its cheaper to do the work myself, and know that its done right. You're telling me that i can get 400hp crate engines for the same cost as if i built a new motor using the original block?
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From: Lakeland, FL
Cruise-In IV-V-VI-VII-VIII Veteran
St. Jude Donor '03, '06, '17
IF I had a matching numbers engine in any classic Vette that I own, I'd definetely save the original block and build or have a engine built.
The stock 4-bolt block should hold up easily to 600+ HP. However, if detonation or any other unexpected breakage (i.e. crankshaft or rod breakage) occurs, the block can end up with a hole in it. It's a good idea NOT to risk the small block. Save the block to retain the vehicles value and have an engine built that meets your needs. (or buy a crate engine if you find one that has the right power and price!
P.S. My old 406 had very likely over 700 HP (estimated) with the 100 shot of nitrous and it was -a "weak" 4-bolt 400 block. With a well balanced rotating assembly, those blocks (400 and 350 blocks) are good to very high horsepower if the engine is built right! With big shots of nitrous, it is recommended to go with a race block but for any street build, a 4-bolt 350 block should have plenty of strength!
The stock 4-bolt block should hold up easily to 600+ HP. However, if detonation or any other unexpected breakage (i.e. crankshaft or rod breakage) occurs, the block can end up with a hole in it. It's a good idea NOT to risk the small block. Save the block to retain the vehicles value and have an engine built that meets your needs. (or buy a crate engine if you find one that has the right power and price!
P.S. My old 406 had very likely over 700 HP (estimated) with the 100 shot of nitrous and it was -a "weak" 4-bolt 400 block. With a well balanced rotating assembly, those blocks (400 and 350 blocks) are good to very high horsepower if the engine is built right! With big shots of nitrous, it is recommended to go with a race block but for any street build, a 4-bolt 350 block should have plenty of strength!
Last edited by GrandSportC3; Jul 7, 2007 at 06:33 PM.
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Joined: Mar 2001
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From: Living in the Hartland
Good article on using a late model roller 4 bolt truck block.
http://www.popularhotrodding.com/tec...ock/index.html
http://www.popularhotrodding.com/tec...ock/index.html
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From: South of giving a damn
St. Jude Donor '11, '17
I've spent about $6k on my 396 & I could have bought one for that. Major exceptions are that I spec'd the parts and decided which combinations to use. I did buy a new block, but that was only $700. Don't let the number matching guys get to you. In 20 years you'll have a rusted hunk of original engine in the corner & no one will still care about numbers matching & rubber bumpers.
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Thread Starter
Instructor
Joined: May 2005
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From: Layton, UT
thanks for all the replys- i think im gonna try to get a new block, just by the fact that I believe my L48 is a 2 bolt main. I definately want to at least have the 4 bolt main for the block. Anyone have an L82 block for sale- ill consider buying it. 
Drifting
Joined: Feb 2005
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From: San diego ca
I have an original 4 bolt L82 shortblock with the original forged steel crank , rods and forged pistons and a brand new camshaft...only problem is I'm southern California and shipping would probably be horrid.
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From: Layton, UT
[QUOTE=fauxrs2;1560982457]I have an original 4 bolt L82 shortblock with the original forged steel crank , rods and forged pistons and a brand new camshaft...only problem is I'm southern California and shipping would probably be horrid.[/QUOT
Im assuming the stock engine didn't have forged rods and pistons, that was something you added right? What motor did you decide to go with if you pulled this one out? I bet your right about shipping, not sure how i would get the block here to UTah. What price are you looking to get?
Im assuming the stock engine didn't have forged rods and pistons, that was something you added right? What motor did you decide to go with if you pulled this one out? I bet your right about shipping, not sure how i would get the block here to UTah. What price are you looking to get?
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From: State of Confusion
Thread Starter
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From: Layton, UT
Looks like i have some research to do.
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From: State of Confusion
a splayed-cap arrangement has the outer-most bolt-holes at an angle (i.e. - more in-line with the cylinder-bores ), where a 2-bolt block has more meat.
Having 4 bolts on 3 different axis probably keeps the main-caps in-register better, making it unlikely they'd 'walk'-around on the bottom of the block.
Here is a splayed-bolt main-cap - note how the outer bolt-holes are 'angled' to the inner-most holes:
http://paceperformance.com/index.asp...D&ProdID=22874
Drifting
Joined: Feb 2005
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From: San diego ca
[QUOTE=dyanisis2;1560982753]
1978 L-82 had forged steel crank, rods and forged aluminum pistons. The original cam wiped a lobe and a lifter bore needs to be honed before putting back on the road.
I was already building a roller cam motor at the time so I just finished it instead of repairing the original.
oh and $200 just to get it out of my garage
I have an original 4 bolt L82 shortblock with the original forged steel crank , rods and forged pistons and a brand new camshaft...only problem is I'm southern California and shipping would probably be horrid.[/QUOT
Im assuming the stock engine didn't have forged rods and pistons, that was something you added right? What motor did you decide to go with if you pulled this one out? I bet your right about shipping, not sure how i would get the block here to UTah. What price are you looking to get?
Im assuming the stock engine didn't have forged rods and pistons, that was something you added right? What motor did you decide to go with if you pulled this one out? I bet your right about shipping, not sure how i would get the block here to UTah. What price are you looking to get?
I was already building a roller cam motor at the time so I just finished it instead of repairing the original.
oh and $200 just to get it out of my garage
Last edited by fauxrs2; Jul 8, 2007 at 01:00 PM.
Advanced
Joined: Jul 2007
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From: Denver PA, surrounded by Amish
I have an '81 and mine was a 2-bolt main. My block was rebuilt (383 stroker) making about 400-425 HP and I'm very happy with it. I definitely agree that a 2-bolt turned into a 4-bolt is stronger than a stock 4-bolt. The rebuilding wiped clean the S/Ns so I no longer have a collector car. Oh well. It's a blast to drive!
