LT1 Block Question..
On permanent vacation
Joined: Aug 2003
Posts: 520
From: Michigan is a decent state.
Originally posted by EviLZ28
Then why do I have a 94 vette block with 4 bolt mains and a 95 with 4 bolt mains?
Then why do I have a 94 vette block with 4 bolt mains and a 95 with 4 bolt mains?
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Joined: Nov 1998
Posts: 71,094
From: Hell was full so they sent me to NJ
Definitely... ALL LT1 Corvettes are 4-bolt blocks. I checked in the Michael Antonick Corvette manual, and he indicates they are all 4-bolt mains, from the first ones in 1992, through the last of the LT1's and LT4's in 1996. I've never heard anyone even suggest that this wasn't true.
AND... this is the good part.... ALL LT1 factory replacment blocks were 4-bolt mains, so if you managed to get your F-Body LT1 replaced under warranty, you got a 4-bolt block.
George Baxter used the 4-bolt block from an LT1 Corvette for his "quickest LT1"... (9.04 @ 155mph in a 3,900# convertible.)
Interesting quote from the often referenced "Rebuilding the LT1" online article:
Although the LT1 was only around for five years, there were two-bolt and four-bolt blocks, aluminum and cast iron heads, regular and H.O. cams that came with long and short dowels, and three different front covers. There was also the "Baby LT1," the 265 cid version that was the standard engine in the Caprice from 1994-‘96. With all that in mind, let’s take a look at this family of engines and see what goes where.
BLOCKS
350 - There are two blocks, one with two-bolt mains and one with four-bolt mains. They both have the same 10125327 casting number, so there’s no sure way to know which one you have until you get the pan off. However, if it came out of a Corvette, it should be a four-bolt block, and if it came out of anything else, it was supposed to be a two-bolt. GM used the two-bolt block for everything but the Corvette because it had plenty of strength and it weighed a little bit less.
Hoping to hear some documented proof from WheelmanZ28 to support his position. 
AND... this is the good part.... ALL LT1 factory replacment blocks were 4-bolt mains, so if you managed to get your F-Body LT1 replaced under warranty, you got a 4-bolt block.
George Baxter used the 4-bolt block from an LT1 Corvette for his "quickest LT1"... (9.04 @ 155mph in a 3,900# convertible.)
Interesting quote from the often referenced "Rebuilding the LT1" online article:
Although the LT1 was only around for five years, there were two-bolt and four-bolt blocks, aluminum and cast iron heads, regular and H.O. cams that came with long and short dowels, and three different front covers. There was also the "Baby LT1," the 265 cid version that was the standard engine in the Caprice from 1994-‘96. With all that in mind, let’s take a look at this family of engines and see what goes where.
BLOCKS
350 - There are two blocks, one with two-bolt mains and one with four-bolt mains. They both have the same 10125327 casting number, so there’s no sure way to know which one you have until you get the pan off. However, if it came out of a Corvette, it should be a four-bolt block, and if it came out of anything else, it was supposed to be a two-bolt. GM used the two-bolt block for everything but the Corvette because it had plenty of strength and it weighed a little bit less.
Last edited by Injuneer; Aug 31, 2003 at 08:20 PM.
Registered User
Joined: Nov 2001
Posts: 719
From: Summerfield, NC USA
Originally posted by EviLZ28
That is correct. ALL vettes came with 4 bolts.
AND... this is the good part.... ALL LT1 factory replacment blocks were 4-bolt mains, so if you managed to get your F-Body LT1 replaced under warranty, you got a 4-bolt block.
That is correct. ALL vettes came with 4 bolts.
AND... this is the good part.... ALL LT1 factory replacment blocks were 4-bolt mains, so if you managed to get your F-Body LT1 replaced under warranty, you got a 4-bolt block.
Registered User
Joined: Sep 2002
Posts: 1,158
From: Chicagoland Area
Originally posted by Injuneer
Hoping to hear some documented proof from WheelmanZ28 to support his position.
Hoping to hear some documented proof from WheelmanZ28 to support his position.
Sorry, I was wrong. Leave it to Fred to make me look like an ****.
Why don't u like me Fred? I like u 
Registered User
Joined: Sep 2003
Posts: 449
From: southeast USA
..
Vettes had 4 bolt mains with "327" casting on them. F-bods had 2 bolt mains with same cast stamping. LT4s are 4 bolts like Vettes but different profile grind on crank. I know. I've worked on em all- Grand Sport Vette 4 bolt main block same as LT4 also by the way.....
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