Rotating assy balance

Keep the caps on their rods! Auto shop 2nd week stuff. Do this: take the pistons and weigh each, then take material out to make all equal to your lightest *. Then do the rods, weigh each top and note the differences. The top of the rod has a balance pad, take material out there to equalize all to the lightest rod, do the same for the caps. then you really should weight the ends on a hanging scale as YR suggests. Your gonna have a hard time getting a repeatable measurement unless you have a dedicated fixture and scale but you can get very close balancing the assembled rod on a knife edge at the cap seam and then setting the scale at a 90 degree height. Do the same with the big ends on the scale and the little ends on a floating pin if bushed. Press fit will need a close fitting dowel or something as the slightest variation of the support point will give you different weight readings. With the little ends and caps all balanced, your balanced weight should be pretty darned close. * My MP magnum stroker pistons were all over the place, one was so heavy I had to take material off the pin as I ran out of piston material, likewise with the lightest piston, I added a couple shots of MIG wire to the inside of the pin to add a few grams to get it close to the others. All pins were equalized, even weighed the bolts, nuts and ring packs. I had a nut that was +1g! Its easy to get all the parts neutral balanced, much harder to get the rods ends to balance on the jig, but your not looking for perfection, your only looking for maybe +- a few grams. I think static and dynamic balancing was incredibly loose back then off the line and they still ran pretty smooth.