I'm measuring at the largest point on the skirts.........Is another set of pistons the fix? As you can tell.....I'm a technician, I'm only posing as a machinist playing with my own junk. My neighbor is a retired machinist. He's in his 80's so I try not to bother him too much. His shop is closed but I have access to it. I don't have all the knowledge I need but I'm learning.