I certainly plan on bringing the kit to my machinist for balancing regardless of their claims for balancing out of the box.
Moper, you say that the journals have a taper? Rod, mains or both?
K1, I'll check into K1 and see if they have what I need. 4.250 stroke and 2.200 rod journals. I know Callies doesn't make one.
BTW, HP should be in the 650 range (corrected for altitude).