It was cheaper for me to have the crank balanced and use my old flywheel, I assume they are pulling the crank to drill it, if not I would run away. I disagree on the no big deal to drill it, was a big deal for me to get a billet hemi crank drilled and machined right but they may know something I dont. I would ask some questions. Here are the specs from a 360 magnum.
Piston 470
Pin 134
Rod small 225
Rod big 519
Rings 40
Rod bearing 47.6
Recip weight 869
Rotate weight 566.6
Weight per cylinder 1435.6
Bobweight 2002.2

These figures worked for my stock 360 mag 20 years ago, use at your own risk.