Newbie- - - - -unless you have a crankshaft that's broken in half, it can be welded up with a machine called a "submerged arc welder" and reground to any size you need. The cost might be higher than finding a different crank, however. There is a salvage yard in Albert Lea Minnesota that usually has multiple ads on Ebay for stovebolt crankshafts.
Roadworthy- - - -try turning the main bearing cap around- - - -there should not be a noticeable step between the upper and lower bearing shells, since even the thickness of a strand of hair is too much misalignment. There is a procedure called "align boring" (sometimes mispronounced "line bore") which makes all the main bearing bores the right size and perfectly in line, but most machinists recoil in horror from a stovebolt when asked to do that, because the bores are four different diameters. If you're anywhere close to Tennessee, send me a PM- - - -I've got the right equipment, and the job doesn't scare me.
Edit: If there's a step at both sides (not an offset) Jon's on the right track with the mismatched bearing shell idea!
Jerry