Only 10,500 hours?? Why man, it's just getting limbered up!
I just went through this whole scenario with an antique Delco Light generator crank. The crank throw was absolute toast, complete with lumps, bumps and scarring. But it WAS round, miracle of miracles.
I controlled my fear and tried an old time fix from ancient auto days. I clamped two aluminum blocks together and bored a hole between them that was the projected (read, best guess) size of the finished bearing. I then spun the crank a moderate speed between centers on my lathe while clamping grit cloth and LOTS of oil between the aluminum blocks. After SIX HOURS of constant "grinding" and changing grit cloths, I ended up with an acceptable surface. It still had a couple of very minor grooves but there was at least 90% decent bearing surface and was round. Since I'm pouring a new babbitt bearing anyway, an odd size really doesn't matter.
As for using a drill to spin your engine over, I'd rather rig up a small electric motor and belt to one of the flywheels since I suspect the drill will burn up before you're finished.
The point is, that's doing it the hard way. A professional crank grinder might have charged $100 or so, but the surface would be absolutely perfect AND ground to a standard undersize to boot....in other words, like it or not it's worth the money. The biggest question is, can you get oversize rod bearings to fit the new crank surface? If not, there are babbitting services available in the antique auto hobby. You'd end up with and odd sized crank pin and a custom (but re-pourable) rod bearing, so not the end of the world.
