Just swapped my BME 426 7.150"/2.200" aluminum rods for Molnar 7.100"/2.200 steel rods, new Diamond pistons, and .9mm,.9mm, 3mm ring pack. Though the rod was slightly heavier the piston was 15g lighter, the rings 20g lighter. The result was that the reciprocating weight was lighter. All of it beyond the pin. The rotating weight was slightly heavier. The entire bob weight went from 2222g to 2244g. However we were able to remove the 22g from the crank pin side of the crank instead of adding to the counter weight. Therefore the reciprocating weight was less, rotating was equal along with the advantage of thin rings. Win win, we'll see next Friday.
Doug