I have a 93 LT1 with 157000 miles on it. The only thing wrong with it is it smokes when first started and when I get on it. I want to replace it but need a straight answer as to if the Corvette LT1 is a four bolt main or two. I see LT1's on ebay that are two bolt but they say it's out of a Corvette. Thanks.

 

Corvette = 4 bolt main. Fbody = 2 bolt main.

 

Over the years we have seen quite a few 2 bolt LT-1 blocks and I believe I was told that in 1994 there was a some 4 bolt main blocks, Guys that were going to build strokers had us put on splayed center caps.

And most Corvette engines that were automatic tranny's seemed to be all 2 bolt mains as well.

 

I would rebuild instead of replacing. You never know what POS used engine you are buying, it could be worse than yours. For me removing and reinstalling an engine is harder than rebuilding one.

 

I have to question that autos had different engines than manuals. I am still learning. Going back a few years to an 88 L98, 2 and 4 bolt mains, or all 2 bolt?

 

Corvette Lt1's are 4 bolt and Fbodys LT1's are 2 bolt. There were also a few instances of Fbody LT4's that came with a 4 bolt. I believe it was late 96 models. Also factory replacements under warranty were likely to get a 4 bolt.

 

I have done some work on the State police cars over the years and buy the starter they were stamped Corvette and every one of those engines we worked on were all 2 bolt main blocks

 

My 88 L98 engine was a 2 bolt. Can't say about the others though.

 

Over the years we have seen Corvette more 2 bolt blocks then 4 bolts and it seems the 4 bolts were standard tranny's for some reason.

Its really hard to figure out why GM don't use all 4 bolts in the Corvettes!!!

 

Once and for all.....The Corvette LT1/4 motors are 4 bolt main and the F-body (Camaro Z28 and Firebird Tran AM) and all the others were 2 bolt mains. That's it. No if and or buts.

The C4 has been around so long that no doubt people have swapped countless 2 bolts motors for thier blown original 4 bolt motors.

 

No questions about it!!!

 

I believe all L-98's were 2-bolt. Gotta save that extra buck.

 

All l98 vettes are 2-bolt mains and the lt1/4 vettes are all 4 bolt main stock .the camaro/trans ams where all 2 bolt mains from 93-96 and i also heard there where a few special factory built 96 ss camaros with the vette lt4 engine ,im not 100% sure but i think they where built for slp performance.
-84-91 vette 2-bolt main ,84-85 had factory forged pistons the rest 86-91 where cast pistons
-92-96 vettes all where 4 bolt mains
-93-96 camaro/ta ,impala ss,caprice,roadmaster where all 2 bolt mains ,except a few 96 ss camaros with the lt4 vette engine
4-bolt main.
I have built a 92 and 95 vette engine and both where auto trans and they where 4 bolt mains never heard or seen a 2 bolt main vette lt1/4 engine installed from the factory.

 

Thanks for the info.

 

Hello,
Honestly, Why are you concerned? I have built many 'high-end' engines, over the years. I agree that It makes one feel better to have a 4-bolt main block.
But really, the only time a 2-bolt main block fail in the main-cap area was a 'dirt-track' engine that had been revved hard to about 8000 RPM a lot, for two seasons! When it did break a main-cap, it was pulled-off the track for a vibration and had not hurt the block(I could tell from the 'break' that the main had been cracked for some time(and looked like it was from improper install of 'that' one cap)).
I have seen MANY failures do to rods letting go!
I don't understand why so many folks worry about the mains so much but should be more concerned about the rods/rod-bolts!
I am comfortable with a 2-bolt main block(especially with small-blocks) that is running a set of 'top-of-the-line' main-stud sets. I would rather spend that money on 'top-of-the-line' forged, cap-screw rods!
I would like to hear from anyone who has built more than thirty High-performance engines(not counting some stock rebuilds) and see if any of these folks can count up main failures and rod failures differently. I know from a lot of engine builders that they all see the rods 'let-go' a lot, and rarely see a main/block failure(short of large doses of nitrous...and when those go, there is so much tore-up that you can't honestly tell which single part 'gave-up' first!).
You All Take Care and Be Safe, -John

 

L98 87' 2-bolt , 89' 2-bolt both original engines. wro87

 

I went just the opposite.

Swapped a 2 bolt for a 4 bolt. (84 vette)