The Pontiac OHC engines I've taken down had Chevy part numbers on the cranks. From what I've seen, the cranks are the same.
It's also my understanding that you will be better off with a 250 12 weight crank instead of a 230 which only has 6 weights. Less internal stress in the crank at high speed with 12 counterweights.
You should consider using a 292 crank in your Poncho. No camshaft in the way! I'm pretty sure it's a drop in except for wristpin clearance. You will need to alter the counterweights according to your choice of connecting rod but that's not a big deal.
