Originally Posted by TRBenj
Except for the PCM ZR-450 ("6.0L HO"), which has a PCM-specific cam, I believe all the 5.7L and 6.0L engines being used by the different marinizers all come from GM with the same long blocks. The difference in hp shouldnt be huge, as the only differences lie in the exhaust and ignition systems, and the tune that theyre running (air/fuel curves). I doubt youre going to see huge variations in hp like the #'s on the 5.7's in that chart would suggest.
The proof will be in the pudding PT... we'll line that new tug up against the local 196 6.0L and see what she's got. What prop came on that thing?
Thing is, there are several variations, of those engines, that GM offers. (Which is the same way that PCM makes the 6.0HO...... They just use a different long block assy.)
CARB requires that the engines be dyno'd using SAE standards. Ilmore is the only manufacturer that uses SAE standards to rate their engines. That is why Ilmore engines actually test at the level that they advertise. They use the CARB criteria to rate them.
SAE standards require that all pumps, belts, manifolds, cat converters, alternator, etc. be on the engine, when it is dyno'd. Ilmore does this, and the other marine manufacturers do not. They dyno the engines with shop headers and no belt driven components on the engine. (Which is how the marine industry has always done it in the past) That is why the CARB numbers are lower than advertised on those engines.