Total rearend change out
 

I have a 1970 Chevy Longhorn that has a one-ton posi-track rear end. I want to put a stadard 3/4 ton in to replace it. My truck is a 350/350 turbo. Does anybody know what years of chevy trucks would fit? New to the site.:flag:

Welcome to the board.
As far as i know, the only rear that will swap directly with no mods is one from another Longhorn.
Why are you wanting to down grade? If your truck is a one ton than you would have the ho72, and a 3/4 ton would have the ho52. The gearing would be the same, just a weaker unit. (4.56 standard onless small block/auto...tehn 4.11 standard)

Welcome to the board from South Mississippi.

What is wrong with your 1-ton axle? Is it broken or does it make your engine spin too fast?

The Longhorn should have the same 40" spring centers as the 4 wheel drive trucks. My 1970 GMC Longhorn parts truck has a Dana 60 in the rear. It also has 3.73 gears. Truck was originally equipped with a POwer Lok that is not there, so gears most likely have been changed.

4.10 and 4.57s are the only thing shown in my restoration catalog from GM, onless you get dauls, then a 5.14 gear goes in.
So if there is a 3.73, then it is not stock.

I do not remember the widths, but CrazyLonghorn has looked into it and said that the longhorn is all alone on spring perch width.

Welcome to the board!


correct me if I am wrong, but the ho52/72 are the same unit, except for the ho72 having larger brake drums. kind of like how in the '73 up models, both 3/4 and 1 ton had the 14bff out back (in most cases).

Nope, the bearings are stronger and the axle shafts should be stronger.
*I don't know this for a fact....but have been told*
As far as looking at them side by side, I believe they look the exact same.

the debate continues. :)

I thought the diff in the diffs was that an HO72 was for duallies and the HO52 was used on the single wheel 20 and 30 series trucks.


Greg

I found a blurb in my Hollanders years ago that alluded to the HO52 having 2 pinions and the HO72 having 4 pinions.