Sorry for this but I need help with my 1992 K3500

Assuming that it has a tbi454, you're not going to get much better. That gen 454 is the worst BB Chevy made. It had roughly 7.5 to 1 comp and crappy peanut port heads. With hp and torque numbers as low as a typical 350 it wasn't very efficient.

My 91 c3500 got 9.5 on flat ground at 55-60mph if driven at 70 it got 8.


Edit: make a post over at ck5.com in the garage forum. They are always helpful and really know Chevys.