Pilot bushing

All the 340 cranks I've seen were all machined for a bushing. Maybe the crank is out of something else? Rather than hone the hole and cut down a stock bushing, I think I'd just get the Magnum BEARING version. It fits into the converter button hole instead. This is assuming that you aren't working with a '67 and earlier 273 crank. In that case, you have no other choice but to make a bushing to fit.