Weighed the 89mm J35 English Racing Spec today! x5 pistons were 372g, x1 piston was 371g. All six wrist pins were 137g. These are going into my 1000hp build. I will have to build a connecting rod weighing scale Contraption you accurately calculate the weights of the small and large side. This is done to have balance with higher than standard RPMs in a built motor.