Rear End Widths Clarified

[SactoJim]

SO....all earlier trucks 67, 68, (what's the cut off?) had 6 lug axles...period....and those 6 lug rearends were a bit narrower than the later 5 lug rears (1" or..?). So they changed to 5 lug (what year?) and the rear end is a little wider and 6 lug was only for 4wd...correct?

So in order to have the narrower rearend, it had to be from an early 6 lug truck and if you want 5 lug, you have to have the axle flanges redrilled?

So is it safe to say that from 67-72 there were just 2 rear ends (1/2 ton) available...early (6 lug) and later (5 lug)?