400 big block

I probably didn't answer any questions you had there...I just looked at the pistons you mentioned there...the 215 and 280 pistons are 400 stroker pistons (3.75" stroke) and are made to fit the relieved heads (906 452 346) with the correct head gasket and proper deck clearance. If you use 915/516 heads, then yes-you'd hit...in a bad way. The other two part numbers you mentioned (241 252) aren't even for a Mopar V8...the 241s are for a 4 cylinder, and the 252s are for a Chevy.