340 Nodular or 318 steel crankshaft

I'm building a 72 model 340 and I have both,(340 Nodular and 318 steel) the 340 has never been turned and mic's out as to only needs to be polished, the 318 needs to be turned 10 on the mains and 10 on the rods...This is going to be a street beater and I don't think it will see any drag strip action. I have a set of J-heads to go on it and I planing on a hughes whiplash cam, it is going in a 72 Dart with a 4 speed.Which one should be better for me? Thanks!