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)?

[1969k10stepside]

1967-1970 2wd had 6 lug rears on the 1/2 ton.They are narrower than the newer late 70-72s.In 1971 they went to discs w/ 5 lug front and rear.Rear axle was wider like late 70 model year rear axle.In 70 (still 6 lugs) there was some rear axles that were wider like the 71+ 5 lug rear axles.The 3/4 tons were 8 lug all through 67-72.I don't think the 3/4 tons switched to a wider axle like the 1/2 tons,in late 70. So,3 types...67-70 6 lug narrow version.70 6 lug rear with wider rear axle.71+ with 5 lug axles that are wider like the late 70s 6 lug. 1/2 ton 4wd was 6 lug 67-72.

[msgross]

My 68 K-10 had a narrower 12 bolt than the 69-70 C-10 12 Bolt that I am installing now. It was about 1.5" narrower. I can get exact dimension if anyone needs them. Both are 6 lug axles...

[itsmike2k]

I measured my 72 5lug c-10 a week or so ago and the housing from outside of the drum to outside drum was 63 3/4" if that help anyone.. I know the mounting surface is almost dead center of the tubs, atleast by the measurements i have gathered, i dont have a bed yet .. Guess thats why a zero offset wheels works so good on these trucks...

[Palf70Step]

There is about 1.5" difference overall. Just depends on how accurate you measure. Some where in the 1970 model year is when the change occurred. My 70 was bought new in Sept 1970, so it was probably one near the end of the runs. I have heard that the change occurred on those assembled sometime after Jan 1970

[VDOG]

I have a chance to buy a rearend with a posi in it. The guy said its a 72 with 6 lugs amd it was converted to leaf springs. I told him 70 was the last year for 6 lugs he had it under his 56 chevy truck. He lives too far from me to just go and view it and not make a purchase, so are there any marking that will tell me what year it is?

[msgross]

It could be from 4WD, but you said "converted" to leaf...

If he wants to sell it then he owes you a pic of the "guts", only way to be sure....