Manufacturers have tolerances they want to maintain between the piston wrist pin and rod. They mark these "A,B,C" etc. If you're not changing rods, it's not really an issue. However... (and this is just from experience) ....if you didn't mark them when you took them out, I would not re-use them. It has nothing to do with the pistons. The rod journals 'mated' to the crank over the years and mis-matching them to a new journal can cause vibration and can shorten the bearing life, maybe by a lot. Do people do it anyhow? Sure. For the labor to put it all back together, and maybe do the whole thing again, I would replace the rods and pistons the first tim