The Stovebolt Site Forums The Shop Area The HiPo Shop Rear end swap for a 1950 GMC 3/4 ton

I am intersted in swapping my rear end in my 3/4 ton pickup. Since there are no gear and pinions available, my only option is a swap. I was told that according to the Hollander guide, a Ford E350 rear end from 1988-1996 will fit and give me a 3.55:1 gear ratio. Has anyone had any experience with this? Anyone know of another rear end that will fit with minimal alterations? Appreciate the help!

Hi Erin-

I'm no expert on this, but I put a 3.42 from a late 90s S-10 4x4 in my Chevy 3600 and couldn't be happier. Other than needing new spring perches and slight drive shaft modification it pretty much bolted in. There is a slight difference in axle width- I have some offset on the rear wheels.

Now that "Ernest" can go 60+ MPH, I also put a 1/2 ton front axle with a new disc brake kit......... and some seat belts.

Hope this helps- Also, try the "Search" feature- there is lots of info on here about this.

"Since there are no gear and pinions available, my only option is a swap."

Not quite accurate. The available ratios include 5.14:1, 4.56:1 and 4.11:1. You most likely have a 4.56:1 ratio. A 4.11 ratio with a typical 27% OD transmission will give you a final drive ratio of 3.0:1. Keeping the 4.56 ratio and using an OD transmission will give you a final drive ratio of 3.33:1. I am not sure what ou are looking for, but if your rear is in good shape, you might consider a transmission swap for better speeds. With a transmission like the NV4500, your truck would have all the low end grunt of a truck, with the ability to cruise the higway.

Yes, the E350 rear will work. it's a Dana 60, which is also found under Dodge 3/4 and 1 ton vans, as well as many later GM 3/4 and 1 ton vans. One thing to be aware of, almost all of the 3/4 ton versions are semi float rather than full float like the original axle. That will sacrifice some strength if you plan on loading your truck.

Longbox...

How do tell the difference when prowling the junk yard? I might swap my HO52 4.56 for a 3.90, but I want to keep the 8 lugs and would like a full floater. Are all axles with shafts bolted to the outside of the hub full floating, or is there something else I should be looking at?
Thanks

HF
There is very little difference between a 3.90 ratio and a 4.11 ratio. At 65 mph, the difference is less than 170 rpm. You might be able to find the 4.11 chunk that will bolt in to your housing. An Overdrive transmission swap will give a significant drop in rpm without sacrificing the low end grunt.

I am looking for the simplest(?) way to lower the highway revs on my 3600. A 4.11 would be great if I could find one. I am thinking that rewelding spring perches and changing the u-joint is a little less involved than modding a T5, finding the right clutch disc and replacing the driveshaft. I would keep the original rear in case I ever find the elusive 4.11, but as a short-term job the axle change seems simplest.

IMHO much easier to do the transmission swap. The T5 isn't the only OD game in town either. The A833 and NV4500 transmissons are great alternatives and use most if not all of the stock clutch components. The 27%OD of those transmissions would give you an affective 3.34 ratio. Neither of these swaps will require welding, unlike a rearend swap.

Yeah, the Ford Dana 60 fits fine. I stuck one under my 1952 GMC pick up. Only thing I had to do was move the spring and shock mounts. A little quick cutting and welding, and there you go. I was even able to reuse my year 2000 8-lug GMC wheels on it. The rear end's got 3.50 gears and gave me all kinds of top end I didn't have before.

Narrowest Dana 60(8-lug)I could find was like a '68 Ford 250 3:73
Like Hot Rod Dad said, cut and weld spring and shock mounts,modify driveshaft ujoint.
With some fiddling also got the e-brake working.
Stock Chev. wheels wouldn't fit over center hub.Ford and Dodge have a larger center hole.

Yeah I know. But I was able to modify my wheels by widening the center whole about an eighth of an inch. So far, it's worked well. And the center hub covers hide everything.

You've just gotta be willing to do what's necessary and get dirty. But it's a good conversion.