I am glad I read this post. I bought a set of the indy 426-1 heads at the swap meet this weekend and the rocker arm hold downs. I am now debating how many cubic inches to make the motor and I was not aware that the Indy heads took a different piston. Where is the best place to get the pistons? I looked at buying a set from moore and moore at indy this weekend, but didnt. I guess I am glad I didnt since theres were the mopar wiesco pistons.