Measured for pushrods and had to modify the guide plates. I need 6.4 pushrod length. We also measured the cam. A comp 274 which should be .555 Int and .565 Exh came to be .595 int and .575 exh. No worries there. More than enought ptv clearance! this 331 should run like a scalded dog. Will be bringing it to Brad Brand here in GA for the tune.