I want to inject some fact, that the GEN III SBC was first released in the Corvette(Y-body) in 1997 with the LS1. The 2nd usage of the GEN III SBC was in 1998 in the Camaro/Firebird(F-body). Both the Y and F body cars use the aluminum block and aluminum heads which comes with RPO LS1.
The LS1 then was uprated for MY 2001. Horsepower is increased from 345 @ 5,600 rpm to 350 @ 5,600 rpm. Torque increases from 350lb/ft @ 4,400 rpm to 360lb/ft @ 4,400 rpm. (375lb/ft for manuals) compression was 10.1:1.
The 5.7 LS6 was introduced for MY2001 at 385hp@6000rpm/385lb/ft@4800rpm, compression was 10.5:1. The changes from LS1 to LS6 involved different blocks all the way up through the cylinder heads. It was far from an LS1 with different heads. Even the injectors were changed from 3.3 g/sec(26.2 lb/hr) to 3.6 grams/sec(28.6 lb/hr). A new intake manifold was designed for LS6, to cut costs, it was introduced on 2001+ LS1's as well on both the Y and F body cars. It accounted for a 5hp and 5 lb/ft on its own.
Then for MT 2002 the LS6 was uprated +20hp and +15 lb/ft torque to 405hp@6000rpm/400lb/ft torque@4000rpm.
The first time a GEN III SBC was ever used in a truck was for 1999, for the 255hp@5200rpm/285lb/ft torque @ 4000rpm 4.8L LR4, 265hp @5000rpm/320lb/ft torque @ 4000rpm5.3 LM7 in iron block/aluminum head configuration, and in the 3/4 ton truck came the 300hp @4800rpm/355 lb/ft torque @ 4000rpm 6.0 LQ4 which was an iron block/iron head configuration.
The GEN III SBC was in production for two full model years prior to the truck seeing the new engine. The GEN-III SBC was not designed from a truck engine.
The 255hp@4600rpm/330lb/ft torque@2800rpm Vortec 350 L31 continued on in 3/4 ton trucks through MY1999, in the SUV's through MY2000 and in the fullsize vans through MY2002. In Mexico you could get the Vortec 350 through MY2010. In marine form it was available through 2013.
The 2004 ZO6 was a quick beast. Its suspension and tires allowed for bone stock 11 second 1/4 mile passes.
Run #1
1.98 60-foot 12.29 at 117.03mph
Hotlapped run #2
1.96 60-foot 12.16 at 117.84mph
Run #3
1.94 sixty 12.03 at 117.83mph
Run #4
2.06 60-foot 12.21 ET at 117.73
Run #5
1.90 60-foot 1/8th mile 7.80 at 94mph. 11.97 at 118.80mph
OEM 2004 ZO6, right down to the stock air filter
http://www.superchevy.com/features/0...vette-feature/
So much of acceleration run tests, esp. street encounters will be decided by the drivers skill. A good driver may beat a bad driver, even if the bad driver has a 200hp advantage. If you really want to know whats quicker or faster, go to the drags and get those performance characteristics on paper.