320 is way to coarse, I'd go 600 max.. I wouldn't have bothered pulling the crank but now that you have you might call a local machine shop & see what it would cost to have it turned & get new bearings...I know a shop local to me that turns 75% of all the cranks for other area machine shops I can get a kit with the turned crank & new rods & mains for $120.00...