If the LT4 that came in the SLP SS models is rated at 330HP then how is that when you do the conversion to a normal LT1 it says it will make 425HP? I may be missing something but it just makes no sense to me at all help if you can.

 

ive read some stuff online that says it reallydoesnt. i was wondering the same thing

 

The LT4 conversion that they sell has a more aggressive cam then the origional LT4 came with. You'll also hear everyone say that "such and such was under rated from the factory" blah blah. The 330 HP that is advertised on the LT4 that came in the car was done under test conditions where the motor was running under a hood, with all it's periferals(water pump, alternator etc.) and a full exhaust system, the 425 that places advertise is a motor that has a more aggressive cam than the origional LT4 and is running as a dyno queen where all it has to do is push exhaust out of a set of dyno headers, so they see much heigher numbers because the motor doesn't have to drive all of it's extra stuff.

 

Absolutely correct. People that advertise engine power, just bolt the engine on a dyno with no accessories, controlled air temp, optimized intake and exhaust, no alternator, and some don't even hook up the water pump (This is known as gross HP). So when you stick that engine in a car, and hook up everything, there is going to be a noticeable loss of power. (Net HP, which is what car factories use, by government edict).