What rear axle for 2wd 72 C10 do I need?

[clarkjw24]

As the title says. I don't have a clue. A guy said he needed one but I'm not sure what I'm looking for. I deal mostly with 80s 4wd. Will anything work or is there special perches or spring pads. He wants to do a straight swap with as little headache as possible.

Thanks
John

[Longhorn Man]

You need to find out if he has leaf springs or coils.

[chevy_fatman]

You will need a truck 12 bolt, the car ones are different I believe.

[da-burb]

Something with as little change limits you to 1971 or 72 12 bolt from a similar sprung truck, coil or leaf. 73+ will be leaf only and the spring pads will be in the wrong location(if he has leaf) so they would need to be relocated. You can also use a 1970 truck 12 bolt. It should be the same width as 71-72 but you will need to change the axles out because they are 6 lug. Very simple operation if it has to be done. The earlier 12 bolts were narrower so if you find one and are in doubt, measure backing plate to backing plate to make sure it is the same as the 72 he currently has.

[badpeanut]

Please correct me if I'm wrong, but a '73-up leaf spring rearend could be swapped into a '72 2wd leaf spring truck by relocating the shock mounts (wrong location and '73-up has staggered shocks) and by adding a bump stop to the rearend ('73-up bumpstop was on frame instead of rearend). I believe '73-up leaf spring perches are at the same width as the earlier 2wd leaf spring trucks (earlier 4wd trucks have a narrower spring pad width).

I'm basing this on my '72 2wd leaf spring truck, my '72 4wd Blazer, and various '73-up 2wd and 4wd trucks I've looked at and measured.

[dennis111]

Originally Posted by badpeanut

Please correct me if I'm wrong, but a '73-up leaf spring rearend could be swapped into a '72 2wd leaf spring truck by relocating the shock mounts (wrong location and '73-up has staggered shocks) and by adding a bump stop to the rearend ('73-up bumpstop was on frame instead of rearend). I believe '73-up leaf spring perches are at the same width as the earlier 2wd leaf spring trucks (earlier 4wd trucks have a narrower spring pad width).

I'm basing this on my '72 2wd leaf spring truck, my '72 4wd Blazer, and various '73-up 2wd and 4wd trucks I've looked at and measured.

I haven't found anyone who has done this swap but I am comtemplating it on my 2wd 68pu. I know that you are working on a 4wd but figure you may get something from the following observations.

I junked a 78' 2wd and kept the rear because the spring pads were exactly the same distance apart as my 68's (42.5" centers, if I recall correctly.) The bumpers and the shock mounts would need some modification. The shock mounts would need to be moved more inboard and one would have to be reversed.

Other deviations I have found is that the 78's pinion "appears" to jut out about an inch more forward, the spring pads themselves are a little wider (2.5" vs 2.25" on my older 68' 2wd-sounds like not a problem on your 4wd), and the brake lines will need a little modification.

Currently torn between locating a 71-72 rear that will bolt right in or doing the mods to the 78'. I would love to know if anyone else has done it.

[badpeanut]

dennis111, is the leaf spring rearend in your '68 a GM 12 bolt or a Dana 44? Is it narrower than the '78 like has been stated? Does the width even matter unless one has the need to swap in the old axles to retain a bolt pattern?

I, too, am looking at rearend swaps. My '72 2wd GMC leaf spring truck has a GM 12 bolt, but I've come across a '60-'66 GMC with a leaf spring Dana 44. I don't know that a person could get 5-lug axles for the Dana 44 so it might not be a good option. Short of finding a '71 or '72 rearend, I think a '73-up 12 bolt is the best option. I'd like to hear from anyone who has done it.