Rear End - what to do

[jhvaughn]

Need some advice, guidance, recommendations...

I have a 60 C10 with (what I believe to be) an Easton rear end. I'm swapping over to 5 lug. Seems I have two or three options, but am not sure what is best.

Ultimately, would like to run 3:73 gears and posi traction.

1) keep current rear end and swap axles, internals. My concern is that I can't swap out the gears and change it over to posi. I believe I read on the forums that there weren't many "upgrade" options for these rear ends.

2) get my hands on a 67-72 off of a C10 and swap out gears and set it up for posi. (currently looking around for one)

3) buy newer rear end from chevy truck (maybe with rear disks) and have it shortened.

Any thoughts from those of you that have been down this path would be greatly appreciated!

Thanks,
Heath

[HackJob65]

It all depends on some variables. What is your budget, skill level, and desired wheel offset. 5 lug axle swap kits are easily available for the 1970 and earlier 6 lug 12bolt rear end. Any GM truck rear end with disk brakes will have 6 lugs. You could get a 10 bolt from an Impala SS or variant, which would have 5 on 5 lug pattern but is wider than your original axle. Narrowing an axle can be costly and make axle replacement a waiting game because of custom ordering.

[jhvaughn]

Would like to keep the costs down. I have a set of 22x9 centerline solids that I'll be running on the truck.

[lumpy63]

I have never done a 60-62 truck but have been informed axle pad location is different from 63-66 trucks. Figure out your wheel offset and tire size and what the over all width you need is. Also your lug pattern 5 on 4.75 or 5 on5.00? several suppliers sell rear end mounting kits with axle pads and panhard bar mounts.

[Captainfab]

You will not be able to achieve your goals with the original Eaton HO32/33 differential. You will need a '63-'72 12 bolt. Of course the '71-'72 will already have the 5 x 5 wheel stud pattern. The '73-'82 12 bolt or '79-'87 10 bolt could also be considered since you will have to relocate the trailing arm mounts on a '63-'72 anyways. The panhard bar mount will have to be addressed also. The '60 to early '70 differentials are 62" wide. The late '70 to '87 differentials are 63.5" wide.

If you do need a new set of trailing arm mounts, those are one of the many products that I make and sell here on the forum.

[jhvaughn]

Thanks Captainfab! Great info. May have to hit you up for one of those brake booster adaptors too when I get to that part of the build.

[63burban]

Just curious, why do you want a posi ?

[jhvaughn]

Because I want to run an LS motor and I want both tires to hook up. Not sure if limited slip will suffice and don't want to run a locker.

If posi isn't necessary, don't have to run it. I'm pretty sure I'll suffer some on gas mileage when on the highway.

[siggyfreud]

You are aware that a limited slip and posi are the same thing yes? One was just GM's marketing terminology.

[jhvaughn]

I thought that but had heard different from others.

[AcampoDave]

Pretty sure I have seen the limited slip in Blazers at the junk yard.

[siggyfreud]

Originally Posted by jhvaughn

I thought that but had heard different from others.

Posi is short for posi-trac, which was short for positive traction. It was GMs marketing term for their limited slip differentials.

Other companies called it sure-trac, tru-trac, etc, but they were all limited slip differentials.

It's not uncommon for people to think they're different things, so not surprising you had heard it . I just talked a guy recently out of swapping his limited slip 3.23 for a posi 3.23 simply because he wanted a posi.

[verdell]

Originally Posted by jhvaughn

Need some advice, guidance, recommendations...

I have a 60 C10 with (what I believe to be) an Easton rear end. I'm swapping over to 5 lug. Seems I have two or three options, but am not sure what is best.

Ultimately, would like to run 3:73 gears and posi traction.

1) keep current rear end and swap axles, internals. My concern is that I can't swap out the gears and change it over to posi. I believe I read on the forums that there weren't many "upgrade" options for these rear ends.

2) get my hands on a 67-72 off of a C10 and swap out gears and set it up for posi. (currently looking around for one)

3) buy newer rear end from chevy truck (maybe with rear disks) and have it shortened.

Any thoughts from those of you that have been down this path would be greatly appreciated!

Thanks,
Heath

For my '60 shortbed, I found a '65 12-bolt rear with 3.07s and had a machine shop to move the mounting brackets and weld them back. Had another gentleman to re-drill the original 6-lug axles to 5 x 5 and had the axle center turned down to fit the 5 lug drums. Worked fine. Saving up for posi and 3.42's now..