These heads and pistons were raced on season on Dirt tracks. Theses heads were so good that Ford bought them from the developer. We bought the Ford revisions the following year. Each valve costs $80.00, 15 years ago. The pistons are childs and albert 12;5 to 1 and match the heads. These heads take a Chevy Big block headers. The pistons have the pins and some locking rings may be missing, They should always be replaced anyway. The bore is 4.375 for these pistons forged pistons I will sell all together or separate. This is so cheap when these heads costs 1500 dollars each completely bare with nothing on them. They produced a lot of power ask the Chev 454 owners we beat. Modified Stock Cars.