[A26B]

Originally Posted by tpepmeie

Jerry,
I weighed up a stock 90 bottom end parts. The pistons actually came it at an average 710g, but close enough to your figure. Range was 708-713.5g.

My sampling of bare piston weight:
"A" pistons @ 483~487gr, avg of 484gr
"B" pistons @ 479~483gr, avg of 482gr (2gr lighter)

Pins, retainers & rings are much more consistent, so the variance probably comes down to the bare piston and the basis GM used for sorting pistons in "A" & "B" groups.

I had in my notes around 538g for rotating weight on the rods. I didn't measure it, though, so can't be sure where I got that from. Probably took the % from a prototype lotus build sheet I saw. Should get you pretty close. That includes the bolts.

Much needed info Todd. Thanks!