Did this years ago, 400 block, 400 rod low comp 440 piston. The cast Sealed Power piston with a cast crank has a bit of a clearance issue, due to the "square" edges of a cast crank. A steel crank doesn't have these "square" sides to the counter weights and should clear the skirt. In this build, budget was key, so cast it was and small trim to the piston skirt.