Chevy Truck Rear-End Swap
The 82-newer Camaros are wider than the older ones, so you should stick with the 70-81 models. The 75-79 Nova uses the same rear as these older Camaros, I believe. The 68-74 Nova chassis is the same as a 67-69 Camaro; the 75-79 Nova chassis is the same as the 70-81 Camaro. The 82-newer Camaros used the small 7.5″ rearend design that the 78-newer Malibu/Monte Carlo/regal/cutlass etc used, but it’s quite a bit wider. Some of the 82-newer Camaros used different rearends, such as the Dana 44, and some weird Australian rear end. Of course, if you want to make sure, get out your tape measure and check yourself! I may be wrong
Here’s another one from Jim on the subject—- There are lots of rear ends available! Some fit better than others. For 6 lug rear ends, the 64-69 1/2 ton 2wd Chevy (and some GMC) trucks have a 12 bolt rear, about 60-61″ wide (I measure them where the wheels bolt on). The 70 2wd and 70-81 4wd have a 6 lug 12 bolt that is a couple inches wider, but will fit under a Task Force truck as long as you don’t get too wild with wheel/tire width.
The 12 bolt truck rearends from the 60s usually had 3.70 gears, which is a bit much for extended highway driving at 75 mph. You can swap the differential carrier and ring/pinion gears from a later TRUCK or VAN 12 bolt, the 70s trucks usually had 3.08 or 3.40 gears. Of course, you’ll need to know how to set up ring/pinion gears, bearing preload, and all that other neat stuff to do this. These 60s truck 12 bolt rear ends are from coil spring trucks, so the perches are in the wrong place, and they have some extra stuff on the housing for a panhard bar, which you won’t need with leaf springs. Most 60s GMC trucks, and some Chevys, had Dana 44 or Dana 60 rear ends, and leaf springs.
These rear ends are 6 lug, about 60″ wide, and will bolt into a Task Force truck (with some fudging, the perches are about 1/2″ too far apart). The brakes use different parking brake cables, which is a problem, and the drums have a different offset. Gear ratios range from 3.21 to 3.92 normally, the 3.21 is found behind some GMC V-6 engines, and is a nice ratio for an oletruck. The Dana 44 uses a standard Chevy 1310 yoke, but the Dana 60 uses a heavy duty yoke, which takes a larger 1350 series ujoint.
A similar Dana 40 rear end was available as an option in 59 Chevy trucks, equipped with positraction…rare, and with a 3.92 ratio. I have one of these rearends, it was in my extended cab truck…I’m saving it for when I build a race truck (one of these years). The 71 and newer 2wd trucks use a 5 lug 5″ bolt pattern, same as the 71-76 full size cars. There is not much available in the way of matching front brake rotors that will fit an old truck, so this rearend is not too popular a swap, unless you get the 70-up 4wd 6 lug axles.
Chevy also used 10 bolt rear ends in lots of cars, in varying widths. A common one is the 61″ wide 70s vintage Camaro/Chevelle/Nova (and clones) 8.5″ rear end. In Camaros/Novas it has leaf springs, but the perches won’t work with old truck springs. In Chevelles, it has coil springs, with lots of extra brackets to cut off, and the cast in mounting “eyes” on top, where the upper control arm bushings fit. Wheel bolt pattern is 4.75″, and there are front disk brake kits available to match, or you can use the 53-54 car front hubs/drums on the original 50s truck brakes, to get the same bolt pattern front/rear. This is a good rear end for using in an old truck, the ratios are commonly 2.73-3.36, with higher gears available.
The axle shafts are usually worn out in these things, so check them (pull the cover, lock pin, and C clips out to get them loose) where they ride in the wheel bearings…before buying the rear end! The 55-57 Chevy car rear end is almost a bolt in, the perches need to be relocated to the top of the housing though. It has the 4.75″ bolt pattern, and ratios are usually 3.55-3.73, but sometimes you’ll find a 3.36. The 78-88 mid size GM cars use a 7.5″ 10 bolt, which is about 58/5″ wide. This rear end would work well in an early (older than 47) truck, but it is quite light duty.
Ratios are usually 2.29-3.23, which means you want some torque in the engine to pull it…but rpm will be low. This is a coil spring rear end, with all the mounting brackets that need to be cut off. The Ford 8″ and 9″ rear ends come in a whole bunch of varieties, and only a few are useful in oletrucks. The late 50s full size cars have a nice one, but it’s not easy to find brake hardware, drum, etc anymore. The mid 60s midsize cars, such as the Fairlane, have a rear end that is about the right width, and would be a good candidate…if you can find one. The Maverick/Granada is very narrow, about 56.5″, and would not fit anything but a very early truck, or perhaps a tubbed Pro Street truck.
The 60s full size Ford car rear ends are usually too wide, but if you find one, measure it and see! Most earlier full size, and all mid size, cars use the 4.5″ bolt pattern, while later full size cars use the 5″ pattern. The Ford trucks have a big 5 on 5.5″ pattern, with a big center that takes some work to re-drill to anything Chevy. Ratios range from 2.47 to 4.30, and the axles come in 28 or 31 spline varieties.
There is lots of interchange possible with the 9″ rear end, which is why it’s so popular…I have one in my 55 Belair, and in my 57 Suburban chassis. Unfortunately, they are getting expensive, especially when you have to shop around for just the right one that will fit. So…if you don’t know if a rear end will fit, or what it came from, get out your tape measure and see for yourself! The most important things are overall width, and wheel bolt pattern…then concern yourself with ratio.
I like a 2.75-3.0 ratio for a V-8 powered truck that will spend lots of time on the highway; about 3.2-3.7 for a 6 cylinder or small V-8 for in town and limited highway use, and the stock 3.9-4.56 ratio is great if you have to use your truck to haul lotsa weight, and you don’t have much engine…just don’t plan on going much faster than 55!