5.3 Vortec Motor, Camaro or TransAm Accessories and Intake( or Fast etc..), could get away with a t-5 but they are junk, go T56, LS7 Clutch and Flywheel. Headers, Intake, Exhaust, and tune will get you 300whp, cam with get you another 20 or so. No need to get ls1 heads. Did I mention 25-30 mpg...