See all the holes welded into the cranks' counter-weight? Those holes were made when the crank was originally balanced for Mickey Thompson aluminum rods. I never ran them. (sold 'em) Instead these are LS7 rods. The LS7 was never released by Chevrolet. But another friend was a NASCAR racer and knew people in high places. These rods came with a race engine he bought from Chevrolet Racing. He took them out because he instead ran Carrillo Rods . He offered them to me for a price I couldn't refuse. They were shot-peened and magnufluxed, plus the bolts are 7/16" boron. They require about 110 ft lbs of torque to reach the specified .009 stretch. The pins are full-floaters with true-lock retainers. Pistons are Speed-Pro 12.5:1 forged.