Is the L98 engine in the 1990 Trans Am GTA same as in the Corvette?
#1
Thread Starter
Junior Member
Joined: Oct 2004
Posts: 25
Likes: 0
From: Baltimore, Maryland USA
Car: 1990 Trans Am GTA
Engine: 5.7 liter, 350 V8
Transmission: 4 speed auto.
Is the L98 engine in the 1990 Trans Am GTA same as in the Corvette?
I have a 1990 Trans Am GTA. When I got it from the dealership, they told me that the 5.7 liter, 350 cu. in. V8 (Tuned Port Injected) engine was the same engine that was put in the 1990 Chevy Corvette.
Is this true?
Thanks in advance!
adreed24
Is this true?
Thanks in advance!
adreed24
#4
Supreme Member
iTrader: (2)
Joined: Jan 2003
Posts: 1,083
Likes: 0
From: Northwestern Pennsylvania
Car: 1985 Pontiac Trans Am
Engine: 355 with stuffs.
Transmission: 700R4
Axle/Gears: 4.10 Posi
Along with the aluminum heads, I believe that the Corvette also had a different cam than the L98 for the FBody.
#7
Joined: Sep 2005
Posts: 26,557
Likes: 1,885
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
B2L is not an engine. Likewise, you couldn't go to the dealer and order RPO L98.
B2L is the package that installed the L98 into one of these cars. It included the engine itself as well as other things deemed necessary or appropriate to support it; for example, an oil cooler.
The L98 in the F cars was very similar to, but not the same as, the version used in the Vette. The single biggest difference is the heads. F cars got cast-iron ones, but the Vettes got aluminum ones. The aluminum ones had smaller chambers, which give higher compression, which is necessary to obtain equivalent performance since aluminum "loses" more heat by conduction out of the cylinder. And, since the aluminum ones lack the exhaust crossover passage, the EGR was plumbed externally.
Other than that, there is very little difference. 2-bolt vs 4-bolt is a very very very minor thing, with zero effect on HP output or reliability in the application at hand (The factory's implementation of 4-bolt main caps is more suited to trucks.... although it could be argued that TPI is too.) Power output was within a few HP of the same, depending on years. The Pontiac cars always had a little less power than any of the others with TPI, because of the inferior air intake that the lower hood line required.
There is no difference between a TPI motor in a GTA and the same motor (305 or 350) in any other Firebird variant of the same year. And there's no difference between the Firebird and Camaro motors except for the air intake, AFAIK.
B2L is the package that installed the L98 into one of these cars. It included the engine itself as well as other things deemed necessary or appropriate to support it; for example, an oil cooler.
The L98 in the F cars was very similar to, but not the same as, the version used in the Vette. The single biggest difference is the heads. F cars got cast-iron ones, but the Vettes got aluminum ones. The aluminum ones had smaller chambers, which give higher compression, which is necessary to obtain equivalent performance since aluminum "loses" more heat by conduction out of the cylinder. And, since the aluminum ones lack the exhaust crossover passage, the EGR was plumbed externally.
Other than that, there is very little difference. 2-bolt vs 4-bolt is a very very very minor thing, with zero effect on HP output or reliability in the application at hand (The factory's implementation of 4-bolt main caps is more suited to trucks.... although it could be argued that TPI is too.) Power output was within a few HP of the same, depending on years. The Pontiac cars always had a little less power than any of the others with TPI, because of the inferior air intake that the lower hood line required.
There is no difference between a TPI motor in a GTA and the same motor (305 or 350) in any other Firebird variant of the same year. And there's no difference between the Firebird and Camaro motors except for the air intake, AFAIK.
Trending Topics
#9
B2L is not an engine. Likewise, you couldn't go to the dealer and order RPO L98.
B2L is the package that installed the L98 into one of these cars. It included the engine itself as well as other things deemed necessary or appropriate to support it; for example, an oil cooler.
The L98 in the F cars was very similar to, but not the same as, the version used in the Vette. The single biggest difference is the heads. F cars got cast-iron ones, but the Vettes got aluminum ones. The aluminum ones had smaller chambers, which give higher compression, which is necessary to obtain equivalent performance since aluminum "loses" more heat by conduction out of the cylinder. And, since the aluminum ones lack the exhaust crossover passage, the EGR was plumbed externally.
Other than that, there is very little difference. 2-bolt vs 4-bolt is a very very very minor thing, with zero effect on HP output or reliability in the application at hand (The factory's implementation of 4-bolt main caps is more suited to trucks.... although it could be argued that TPI is too.) Power output was within a few HP of the same, depending on years. The Pontiac cars always had a little less power than any of the others with TPI, because of the inferior air intake that the lower hood line required.
There is no difference between a TPI motor in a GTA and the same motor (305 or 350) in any other Firebird variant of the same year. And there's no difference between the Firebird and Camaro motors except for the air intake, AFAIK.
B2L is the package that installed the L98 into one of these cars. It included the engine itself as well as other things deemed necessary or appropriate to support it; for example, an oil cooler.
The L98 in the F cars was very similar to, but not the same as, the version used in the Vette. The single biggest difference is the heads. F cars got cast-iron ones, but the Vettes got aluminum ones. The aluminum ones had smaller chambers, which give higher compression, which is necessary to obtain equivalent performance since aluminum "loses" more heat by conduction out of the cylinder. And, since the aluminum ones lack the exhaust crossover passage, the EGR was plumbed externally.
Other than that, there is very little difference. 2-bolt vs 4-bolt is a very very very minor thing, with zero effect on HP output or reliability in the application at hand (The factory's implementation of 4-bolt main caps is more suited to trucks.... although it could be argued that TPI is too.) Power output was within a few HP of the same, depending on years. The Pontiac cars always had a little less power than any of the others with TPI, because of the inferior air intake that the lower hood line required.
There is no difference between a TPI motor in a GTA and the same motor (305 or 350) in any other Firebird variant of the same year. And there's no difference between the Firebird and Camaro motors except for the air intake, AFAIK.
What about pistons? Aren't the pistons on the Vette L98's different than those on the Camaro L98? And the cams are the same?
I have a shortblock L98 out of a Vette that I'm putting in my Camaro with factory Cast Iron thirdgen L98 heads and, in my research, noted a thread in which someone mentioned they had problems with detonation on a similar setup. Basically, they claimed that the Vette L98 bottom end with thirdgen L98 cast iron heads had such a high quench that it would detonate BAD no matter what. This was due to the vette pistons lowering the compression ratio with the larger chamber cast iron heads, as they were designed for the smaller chamber aluminum heads. Any thoughts?
#10
Supreme Member
Joined: Oct 2006
Posts: 1,974
Likes: 0
Car: 91 RS
Engine: 350 vortec
Transmission: T-5
Axle/Gears: not the best not the worst
pick the right head gasket will solve the quench... but that doesnt mean it wont detonate... but i dont under stand what you mean the vette L98 rotating assy. and the Fbody should be the same... they used smaller cc heads to change compression in the vette...
#11
Someone mentioned that the Vette pistons are different enough that they would lower the compression by about one point (in comparison to a third-gen L98) when used with cast iron L98 heads .
I'm worried that, even using a FelPro shim metal head gasket (.015" compressed thickness...approximately the same as the factory head gasket at an estimated .016"), I'll still have too much quench AND a low CR.
I'm worried that, even using a FelPro shim metal head gasket (.015" compressed thickness...approximately the same as the factory head gasket at an estimated .016"), I'll still have too much quench AND a low CR.
#12
Supreme Member
Joined: Oct 2006
Posts: 1,974
Likes: 0
Car: 91 RS
Engine: 350 vortec
Transmission: T-5
Axle/Gears: not the best not the worst
okay well CC the piston head and find out measure the compression distance and rod length then determine how many cc's they add to combustion chamber if you need to replace them hypers can be had for $11 a piece...
#13
Supreme Member
Joined: Apr 2002
Posts: 3,552
Likes: 5
From: New Jersey
Car: 86 Corvette, 89 IROC, 1999 TA
Engine: 350, 350, LS1
Transmission: 700r4, 700r4, T-56
Axle/Gears: 3.07, 373, 4.10
Not all L98 vette's came with aluminum heads, my 86 came with cast iron heads, KB2- CAST IRON CYLINDER HEADS and L98- 85-91 STANDARD ENGINE, 350 250HP TUNED PORT INJECTED as per my rpo list.. I think sometime in 86 they switched over to aluminum heads.. not positive.. if anyone knows for sure I'd love to know!
#14
Member
iTrader: (1)
Joined: Jul 2006
Posts: 194
Likes: 0
From: Baltimore, MD.
Car: 1967 Camaro
Engine: 327
Transmission: Turbo 350
Axle/Gears: 308's
Not all L98 vette's came with aluminum heads, my 86 came with cast iron heads, KB2- CAST IRON CYLINDER HEADS and L98- 85-91 STANDARD ENGINE, 350 250HP TUNED PORT INJECTED as per my rpo list.. I think sometime in 86 they switched over to aluminum heads.. not positive.. if anyone knows for sure I'd love to know!
#15
Yeah, but I'm not planning on ripping apart the bottom end, and I can't use anything but stock pistons for the auto-x class I'm running in. I'm just wondering if Vette "stock" is the same as Camaro "stock". I guess I could go to a chevy dealership and try to cross-reference part numbers...
Thread
Thread Starter
Forum
Replies
Last Post
84z96L31vortec
Tech / General Engine
7
08-20-2017 12:16 AM
84z96L31vortec
North East Region
1
08-10-2015 08:27 PM