Gross Horsepower LT-5

[Hog]

Originally Posted by Hib Halverson

The only gen II LT1 which made 300 SAE net was the version in Corvettes and it was available from 1992-1996 with automatics and from 1992-1995 with manuals. That engine never made "377-78" gross at the flywheel. More like 340-350 on a good day.

The Camaro used a less powerful version (275-hp SAE net) of the Gen II LT1 from 1993-1997. There also was an even milder version (260-hp SAE net) used in the Caprice and Impala of the mid-90s.

The Gen II LT1 was, also, not the most powerful "traditional" (Gen 1/Gen II) SBC. That honor goes to the LT4, used in 1996 manuals. It made 330 SAE net about about 370-380-gross hp.

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Obviously I was referring to the 92-96 Y-body Vette LT1, although there isnt much different power productionwise between the F-Body and Y-body LT1(cam, exhaust, air intakes). There were 315hp F-body LT1 engines with optional intakes and exhausts.

You are correct about the LT4 being the highest output GEN I/II engine. The material I was referencing was written in 1994 hence my oversite of the LT4 which was used in the 96 Vettes and the 135 1997 Camaro/Firebirds(which actually use a stock LT1 F-body calibration, for emissions, without the Vette LT4's 6412 rpm rev limit, along with extrude-honed stainless steel exhaust manifolds and balanced and blueprinted longblocks UNLIKE the stock 1996 Y-body LT4's). The LT4 was a great engine, LS1 power in the standard 4" x 3.48" GEN I/II package. 1997 LT4 SS Camaro runs high 12's same as a a stock LS1 equipped 98-02 Camaro, both equipped with the T-56 trans of course.

I respectfully disagree about your LT1 hp assertions.
The 1970 LT-1 was rated at 370 gross hp.
The 1971 LT-1 was rated at 330 gross hp(less cr)
The 1972 LT-1 was rated at 255 SAE net hp. (little difference to the 71 LT-1).
The 92-97 LT1 Y-body engine outputs more gross hp than any GEN I engine, even the 70's 370 hp LT-1 and the 60's 375 gross hp L84. This fact is in print by sources including GM.

To complete the GEN II story, yes, the LT1 was used in the 94-96 B-body(Caprice/Wagon/9C1 Police PAckage,Impala SS, Buick Roadmaster/Wagon), 94-96 Cadillac Fleetwood. Although these LT1's used iron heads which flow slightly more than the aluminum Y/Fbody cousins. All 94-96 iron headed LT1's used the same 191/196 0.412"/.428" 111ºLSA which is also shared by the 1996-2002 L30 Vortec 305 230hp at 4600rpm/280 lb/ft torque at 2800rpm, and 96-2003 L31 Vortec 350 with 255 sae net hp at 4600rpm/330 lb/ft torque at 4600rpm.
This same roller cam is also used in the other "baby" GEN II engine, the 94-96 4.3l 265 cid V8 RPO L99 that made 200 sae net hp and 245 lb/ft torque used in the B bodies. This engine got better fuel economy than the 5.7 LT1. The 4.3 V8 uses a 3" stroke crank and special length 5.94" PM rods coupled with 3.736" Vortec L30 305 pistons to get to the 265 cid. If this 3" 2 piece RMS crank is dropped in any 1 piece RMS 4" bore block and you now have a more modern 5.0 302 SBC engine. GMPP built a GEN II 302 that made over 420hp with 7000rpm capability.



peace
Hog