Is it an LT1
Thread Starter
Advanced
Joined: May 2008
Posts: 53
Likes: 0
Is it an LT1
You may have already read some of my previous threads. Long story short -- I need to replace the LT1 in my 92. I found a salvage motor, and had it shipped to my garage for install. The yard claims it was from a 92 -- the VIN checks out as a 92.
However, the mechanics at my shop tell me it looks nothing like the engine in my car. I am going to look at it Monday -- what should I look for to verify that the salvage motor is indeed an LT1 and not something else (maybe an L98)? Did any L98s have an Optispark?
Worst case scenario -- could I use an L98 short block with the LT1 heads and manifold?
Rob
However, the mechanics at my shop tell me it looks nothing like the engine in my car. I am going to look at it Monday -- what should I look for to verify that the salvage motor is indeed an LT1 and not something else (maybe an L98)? Did any L98s have an Optispark?
Worst case scenario -- could I use an L98 short block with the LT1 heads and manifold?
Rob
Le Mans Master
Joined: Apr 2005
Posts: 6,413
Likes: 9
From: The Old Dominion
No L98's had optispark. Did they say it's from a '92 Y-body? Or just a '92 Chevy? Only the 'vette had the LT1 in '92. The F-body didn't get it until '93 and the B-body until '94.
Near where the VIN is stamped on the block there should be some other manufacturing stampings:
http://idavette.net/facts/92.htm
Look near the bottom of that link. Presumably the block should have either "ZTB" or "ZAC" on it if it's a 1992 MY LT1 from a 'vette.
I don't know enough about the details to answer your second part, except to say an L98 block won't have any provision for the Opti. I don't think you can just substitute in a regular distributor because I think the opti sends some signals to the ECM for fueling, but perhaps that's only on the later SFI motors? I really don't know.
Near where the VIN is stamped on the block there should be some other manufacturing stampings:
http://idavette.net/facts/92.htm
Look near the bottom of that link. Presumably the block should have either "ZTB" or "ZAC" on it if it's a 1992 MY LT1 from a 'vette.
I don't know enough about the details to answer your second part, except to say an L98 block won't have any provision for the Opti. I don't think you can just substitute in a regular distributor because I think the opti sends some signals to the ECM for fueling, but perhaps that's only on the later SFI motors? I really don't know.
Last edited by Aurora40; Aug 7, 2009 at 05:56 PM.
Thread Starter
Advanced
Joined: May 2008
Posts: 53
Likes: 0
No L98's had optispark. Did they say it's from a '92 Y-body? Or just a '92 Chevy? Only the 'vette had the LT1 in '92. The F-body didn't get it until '93 and the B-body until '94.
Near where the VIN is stamped on the block there should be some other manufacturing stampings:
http://idavette.net/facts/92.htm
Look near the bottom of that link. Presumably the block should have either "ZTB" or "ZAC" on it if it's a 1992 MY LT1 from a 'vette.
I don't know enough about the details to answer your second part, except to say an L98 block won't have any provision for the Opti. I don't think you can just substitute in a regular distributor because I think the opti sends some signals to the ECM for fueling, but perhaps that's only on the later SFI motors? I really don't know.
Near where the VIN is stamped on the block there should be some other manufacturing stampings:
http://idavette.net/facts/92.htm
Look near the bottom of that link. Presumably the block should have either "ZTB" or "ZAC" on it if it's a 1992 MY LT1 from a 'vette.
I don't know enough about the details to answer your second part, except to say an L98 block won't have any provision for the Opti. I don't think you can just substitute in a regular distributor because I think the opti sends some signals to the ECM for fueling, but perhaps that's only on the later SFI motors? I really don't know.
Rob
Thread Starter
Advanced
Joined: May 2008
Posts: 53
Likes: 0
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
Block Casting #327
LT1 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.
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 STL94LT1; Aug 7, 2009 at 07:41 PM.
Thread Starter
Advanced
Joined: May 2008
Posts: 53
Likes: 0
Sigh -- it's an L98. The yard has the serial number checking out as a 92, but it is clearly incorrect. Thankfully they have been gracious throughout. They are sitting on a 07 Z06 that has been branded irrepairable -- with enough time and money I could make that work 
Anyway,the search continues.
Rob
Anyway,the search continues.
Rob
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
The giveaway sign for a LT1 if looking at only a shortblock or bare block
is the two holes for the waterpump each side. Gen I only has one each side.
Also as shown the alum timing cover is completely different to a Gen I stamped metal one.
is the two holes for the waterpump each side. Gen I only has one each side.
Also as shown the alum timing cover is completely different to a Gen I stamped metal one.
Last edited by rodj; Aug 10, 2009 at 09:28 AM.
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
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri