Guessing the age based on the grill, if it has the original wheels I would guess that if it is a swb they will be 5" and if it a lwb they will be 5.5", but if it has later model rims they will be swb 5.5" and lwb 6". 6.5" are not standard rims and are either forward control deep dish rims (very rare) or HD (wolf) rims.