I've always measured complete rear ends from Wheel Mounting Surface to Wheel Mounting Surface. On my '46 stake bed it didn't really matter too much since there were no fenders to deal with. I think I'll probably have to wait until the truck gets here and I can measure the space between the fenders to make sure. Looks like there are several 6 lug units out there so it shouldn't be too much of a problem.
Joe
