The Stovebolt Site Forums The Shop Area Engine Shop Narrowed Rear Ends ?

In the almost two years that I have been here on the stovebolt, I have never heard anybody propose a narrowed rear end to fit a newer modeled rear to our vintage trucks. I have to assume that it is very cost prohibitive to do such a modification. One area that I can think of where it would be benificial is on the 3/4 ton and 1 ton AD trucks. They came with 4.57 and 5.14:1 gearing and the carriers to get to 4.11 are apparently hard to find. I have access to several 70's and 80's 3/4 ton rear ends that had 3.78 and other combinations of gears. The brakes are good and they would be easier to get parts for than the AD trucks. The only problem is that they are wider than the AD rears. Maybe some of you drag racers can give me the story on narrowed rear ends. Thanks!!
Ralph

True, but take the measurement at the wheel hubs rather than to the back of the brakes. I've measured some of these rear ends, and they're actually pretty close, but still an inch or two wider.

I think they would still work because in order to use the year 2000 GMC chrome 8-lug wheels on my 3/4 ton '52 GMC, I had to use 1 3/4" spacers. Even with my wheels spaced 3 1/2" further apart than original, they still fit nicely inside the wheel wells. That's why I think a wider rear end would still work. I'd estimate that you could go at least 4" wider than stock, and still fit inside the wheel wells of a 3/4 ton or 1 ton.

When I convert to the Ford Dana 60 3.73 rear end that I'm planning, I'll be able to put the same wheels on without the 1 3/4" spacers and fit perfectly inside the wheel wells. The only work is to adapt the spring and the shocks to work with the truck.
And yes, the same 8-lug wheel pattern will fit with these GMC wheels. The center hubs are different sizes, but they still seem to fit.

Just to fill in some gaps, the spacers have their own lug nuts. If anyone wanted to do what I did, the spacers are a few hundred bucks to have made, but they work well. First you mount the spacers to the hubs with their own lug nuts, and torque them, and then you mount the wheels to the spacers and use a second set of lug nuts for the wheels. They have to be retorqued a couple of times in the next 100 miles, but then they do well.

This allowed me to use some modern tires, which at least doubled the streetability of my old truck. I'm using Uniroyal Laredo 265/70R-16 steel belted radials, and they are slightly shorter than the original "schoolbus" tires on split rims that I had before. 30.6" in height to be exact. This doesn't help my top speed any, which is why I'm looking to put a taller gear in the rear of my truck.

I've heard Patricks has ring and pinion kits to make the stock rear end taller for better cruising speed, but I didn't see anything online at their site. Still, having a modern posi with better tapered roller bearings and modern brakes is more appealing to me than spending all that money to re-gear the stock rear end and still have an open diff, ball bearings, and old brakes.

I narrowed a ford 9 inch to fit in my 34 coupe a few years back. I bought the rear for $50 and the axles were about $300. It's not that tricky to do provided the axles or axle tubes are not tapered. I even had the axles converted to the chevy bolt pattern and redrilled the drums to fit.

I have 58-64 chevy pass car and 93-98 cadillac fleetwood rear ends cut all the time,just 1 1/2" on each side.Costs me $275 which includes cutting the housing/rewelding it and putting it on a jig to make sure it is straight and cutting the axles.The place I use is Sutton engineering in LA.

Very common to do in this area for race cars and 4x4's. Many drag cars, Jeeps and Broncos run around here with narrowed Dana 60's under the rear of them. Roundy round race cars and street rods use 9" Fords. Moser Eng. in Indiana (I think?) can shorten and respline your axles very reasonably. Didn't someone here on the bolt narrow a big Dana rear for a '46 or so 1-1/2 ton just last winter or spring? Might try a search under "Big Bolts".

Thank you all for your quick responses. This seems to me to open up a whole new method to keep these trucks on the road. I have a 77 GMC 3/4 ton that had a 454 and auto. The truck drove very well on the highway and I have always assumed that it had 3.78's or maybe higher gears. I made the truck into a trailer when the engine gave out and it only had 90K miles on it when it was parked. I currently have the 16.5 x 16 wheels and tires on my 48 - 3/4 ton and they fit well on the back. I put the old safety wheels from my pickup on the trailer and it seemed to narrow the whole rear end up. Looks like I need to get the tape measure out and see what we have and what it would take to get it roadworthy. I have not been able to find a carrier to convert it to 4.10, so this looks like a better option. Thanks again guys. Keep the ideas comming.
Ralph

Or you could just buy the T-5 that I have for less than narrowing a rear end.

Phil

I have reasoned the following. I understood that the early camaro rear end was a simple swap to an ad truck. One of the popular camaro swaps was to a Chrysler B body 8 3/4 rear end with removable 3rd member. Pumpkin can be changed easily in under an hour. It seems to me that the same 8 3/4 should easily adapt to truck. Keep street gears, road trip gears, whatever the occasion calls for. Just a thought.

Phil;
Would your T-5 be strong enough for my one ton duallie? I work the truck pretty hard.If you think it would work,we should talk.

Speed

The chrysler B body from the late 60s early 70s will go right under a 53 a buddy of mine has a Dana 60 from a 69 charger under his and it fits perfectly he has big mickey thompson tires on 15x10 centerlines on rear with no fender mods. and truck sitting a little lower than stock.

I have a couple of car rears from a Trans Am and a Cutlass that will work well with a 1/2 ton, but I am dealing with a 3/4 ton with 8 lugs. If I changed to a 5 or 6 lug rear end, then I would have to change the front as well. I have two 1/2 ton chassis that I could fix up and then transfer my body over to, but I like the 3/4 ton and want to keep it as stock as possible and still be safe and drivable. Phil, I am interested in your T-5. I will send you an e-mail. Thank you all for your responses.
Ralph

Speed, I would probably not put a T-5 in a dually that is worked hard. It most likely won't hold up. On the other hand, Oldtmy 48 uses his truck as a daily driver and hauls occational loads of hay. It will hold up for his uses.

Phil

I am thinking of my 51 half ton down the road with my 292 in front of a T-5 and a Trans Am rear. This is my idea of a hot rod over the road truck.
Ralph