I'd think about cutting the counter weights down. When I built the 451 stroker with a factory 440 steel crank, I cut the counter weights .120" in radius for use with 6.76" H-beam rods and Ross forged flat top pistons. Took very little drilling on the crank after that to balance it.
My pistons were 510 gms and the pins were 158 gms. Scat H-beam rods for 2.375 journal.
Ask those that are going to do the balancing for you.
