Welcome to the Corvette Forums at the Corvette Action Center!

2 or 4 bolts????

bill81vette

Moderator
Joined
Jan 17, 2004
Messages
4,353
Location
Troy,NY
Corvette
1981 dark blue metallic
Were the corvettes of the mid-80's built with 2 bolt or 4 bolt mains????
some one recently asked me I told them I would try to find out.
just curious..
 
All the L98's are 2 bolts with cast pistons.
84's were different ; had forged pistons and possibly 4 bolt mains.
Corvette LT1's were 4 bolt and F-bodies 2 bolt
 
All the L98's are 2 bolts with cast pistons.
84's were different ; had forged pistons and possibly 4 bolt mains.
Corvette LT1's were 4 bolt and F-bodies 2 bolt

That is interesting. I thought all LT1's were 4-bolts. I didnt realize the F-bodies got 2-bolt mains.

While we are discussing 2-bolt and 4-bolt mains... The 90 - 92 LT-5's were 2-bolt and the 93 - 95 LT-5's were upgraded to 4-bolts.

Jason
 
LT5 is a standalone engine built by Lotus, nothing in common with regular SBC .
FWIW;
there are a lot of differences in bolt on parts across the LT's especially different balancer setups; Vette v F-body
Many people have been caught out when trying to fit a LT1 from a F-body into a C4
 
LT5 is a standalone engine built by Lotus, nothing in common with regular SBC .

GM does not even consider the LT5 to be a small block. The only thing it has in common with a small block is its displacement. The engine is so big and heavy it is considered a big block. GM even billed the LT4 as the most powerful small block motor it had ever put in a Corvette.

I only mentioned the LT5 because we were talking about C4 motors. :upthumbs

Jason
 
Corvette LT1's were 4 bolt and F-bodies 2 bolt

This is correct. I toasted my bearings in my '94 LT1, and had to replace the block, the engine builder had one from an Fbody that he gave me without charge, so I gladly accepted, the only down size was the 2 bolt mains. Now I have a 383 stroker with all forged internals, but with the 2 bolts mains being the weak link. ;shrug
 
This is correct. I toasted my bearings in my '94 LT1, and had to replace the block, the engine builder had one from an Fbody that he gave me without charge, so I gladly accepted, the only down size was the 2 bolt mains. Now I have a 383 stroker with all forged internals, but with the 2 bolts mains being the weak link. ;shrug

I've always been of the belief that unless your motor spends a lot of time well over the 6000 rpm mark, then 2 bolt mains are enough.
 
GM does not even consider the LT5 to be a small block. The only thing it has in common with a small block is its displacement. The engine is so big and heavy it is considered a big block. GM even billed the LT4 as the most powerful small block motor it had ever put in a Corvette.

I only mentioned the LT5 because we were talking about C4 motors. :upthumbs

Jason

LT5 is a standalone engine built by Lotus, nothing in common with regular SBC .
FWIW;
there are a lot of differences in bolt on parts across the LT's especially different balancer setups; Vette v F-body
Many people have been caught out when trying to fit a LT1 from a F-body into a C4

Technically the engine was designed with the same bore center to bore center as the SB, something that the Chevy engineers were adamant about, because Lotus wanted to change that measurement. This, as I understand it, was for production continuity, otherwise there would have had to have been a second production line for the ZR1.

Sorry for the Hijack......:eek:hnoes
 
I've always been of the belief that unless your motor spends a lot of time well over the 6000 rpm mark, then 2 bolt mains are enough.

That was already the belief in the mid 70s. Unless your going to run 7000 RPM or over,there was no need to worry about the two bolt mains. I have seen a lot of very abused 2 bolt main 350s run a very long time.

Glenn
:w
 
All the L98's are 2 bolts with cast pistons.
84's were different ; had forged pistons and possibly 4 bolt mains.
Corvette LT1's were 4 bolt and F-bodies 2 bolt

On the statement about 84s...what's the source of the information?
 
That was already the belief in the mid 70s. Unless your going to run 7000 RPM or over,there was no need to worry about the two bolt mains. I have seen a lot of very abused 2 bolt main 350s run a very long time.

Glenn
:w

I understand, and am of the same opinion, which is why I ok'd the 2 bolt block - although I would for the sake of stress relief, prefered the original 4 bolt, but the journals were toast.
 
  • Thread starter
  • Moderator
  • #13
From everything I've been able to gather,they were in fact built with 2-bolt mains....
 
That was already the belief in the mid 70s. Unless your going to run 7000 RPM or over,there was no need to worry about the two bolt mains. I have seen a lot of very abused 2 bolt main 350s run a very long time.

Glenn
:w

[oldagealert]Uh.....well...uh.....I was around working on motors in the...uh....mid 70's[oldagealert] :eek:hnoes
 
I know from rebuilding my 1982 L83 that it has 2 bolt mains. Should be the same for 1984.
 
I agree. I don't think 84s had forged pistons or four-bolt mains.
I have to do some searching, but I'm pretty sure the L83 had TRW forged pistons.
 
I have to do some searching, but I'm pretty sure the L83 had TRW forged pistons.


General agreement over many years on that other Vette Forum that the '84 CFI was the last with forged pistons.
 
I agree. I don't think 84s had forged pistons or four-bolt mains.

When I rebuilt my '84 (L83 engine), I found 2-bolt mains in it. I didn't notice what the pistons were, but they were good! With 190,000 miles on the engine, it was running fine when the camshaft timing gear gave up. Now I'm working on the next 190,000 miles.
 

Corvette Forums

Not a member of the Corvette Action Center?  Join now!  It's free!

Help support the Corvette Action Center!

Supporting Vendors

Dealers:

MacMulkin Chevrolet - The Second Largest Corvette Dealer in the Country!

Advertise with the Corvette Action Center!

Double Your Chances!

Our Partners

Back
Top Bottom