Yes, stock pistons, even ran the same cam setup in a stock 360 as well. Never hit anything. Ran very good as well. I blew a 68 camaro with a 375hp 396 with the 318. He was a friend of mine. The whole town watched it happen. Well not in the ditch but I beat him by a fender. We both had 4 speeds, he had 3.55's and I had 3.91's. Those were the days.