I used to use spirolocs on piston wrist pins, always ordered extra locs to have around. Once you install a couple becomes easier to install and remove. Always double count the number laid out for assembly and put the extras in the toolbox. I know someone who assembled 427 short block and came across a spiroloc on the stand. I knew all the pistons were correct, but still had to pull it back down to check. They were all correct but couldn't sleep if I didn't check., was an extra I didn't pick up.i may have to contact Murdoch racing for correct size if we need, thanks