As usual I'm late to the party..... but seeing as how I DO see the Engine is now dis-assembled, because apparently it had a 'Balance" problem ?
Why not just get the Pistons pushed off the Rods.....
and go get the entire assembly Balanced properly prior to re-assembly ?
I mean it's just not THAT expensive to get a Bobweight worked up with the Pistons off the Rods... and get the Crank spun up with the Bobweights on a Crank Balancing Machine and SEE just "where" or how far out things are ?
I mean one way or the other it's gotta get fixed right ?
I mean even if you press one Piston off a Rod to get a Rod small/big end split, Piston/Pin/Rings weight..... it's close enough to get a Bobweight and send the Crank out with Balancer/Oil Slinger/Timing Gear and Flexplate installed to get it spun ?
Otherwise.... merely 'guessing' on compatible Rods etc., etc is a gong show waste of time.