My friends Pontiacs had been well into the 10’s for several years by that time. That’s with a net lift at the valve of .410” The rule is .421”, but the stock rockers were never quite “1.5”.
He had the best longevity out of used factory rockers. He’d tested piles of them from used motors to get 16 with the closest to 1.5 ratio as possible.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
