I have never really looked into it. But i know that I have read threads in passing that have said that the 4.2L pistons are different, does anyone know definitively one way or the other?

 

I think I said the pistons aren't the same?

 

From what I read on the link on this thread was that u need to use the 4.2 pistons because of valve clearance and that if u use the mustang pistons the valves will get hit and start tearing up the motor internally, so does that mean the 4.2 pistions have valve releafs on them?