5.9L Magnum build with questions

So that would stand to reason that you could put a set of kb107s into a 5.9 mag with no need to rebalance.

5.9 mag - 469g piston 135g pin 604g total
kb107 - 524g piston 132g pin 656 total

52g difference

I put KB 107's in my 5.9 mag, and mallory was needed and added to the crank.