I did not use a piston stop but I did pull the intake and number one head and watch the piston it lined up with the mark on the timing cover and I did check the chain because I thought it jumped but when I pulled it apart it was still dot to dot just like I put it in four years ago. It is a Cloyes chain Seemed loose when I put it in. So I put on a chain tensioner when I put it back together. Maybe it was Line bored when I rebuild it way back I don’t remember. Another guy was telling a way to see if the cams lined up by the valves I’m thinking about taking the valve cover off and looking at it that way before I take the motor apart again