The Stovebolt Site Forums The Shop Area Driveline What's the best rear axle to swap with?

Forgive me if this topic is discussed elsewhere and I've just missed it. Looked in the Tech Tip section also & didn't see anything there either.

I'm building out my '51 half ton as a mild street rod and will be swapping the 6 banger for a 350 V8 I've already bought and a T350 tranny. Surely after as many conversions as have been made there's agreement about which donor rear axle is the best to use!?!? Obviously you want one that is the correct width and centers in the wheel openings correctly. I've been told to look for old Camaros in the junk yards but I wouldn't know which year is the best. Or would others say that a rear end from an S-10 or other Chevy pickup be the best? I was hoping to find an article by someone who had done all the research and decided on the best choice(s). Any help would be appreciated so I can start searching the wrecking yards.

Thanks!!

Here's a link I found a while ago. It has a bunch of measurements that may aid you in your decision.

www.carnut.com/specs/rear.html

The perfect rear axle is going to be based on your needs. It's no surprise to discover that each of these trucks serve different uses. Some need taller gears for highway cruising, some want shorter gears for hauling, towing, and acceleration.

In addition where you live can dictate gearing. For example, someone with an original 1/2 ton engine (216 or 228) that lives in non-flat areas may find a 3:55 gear set sluggish.

Fox, thanks for the link.I guess a good place to start is measuring the rear axle in my truck and then go from there looking for donors with the same measurement.

Sweet, I plan to drive my truck simply for pleasure. I'd like to be able to cruise at highway speeds and to be able to get better gas mileage with much lower RPMs, so a donor rear axle with the taller gear would suit my needs. No dragracing for me! I will only drive it on the weekends to car shows & the like within a 200 mile radius of San Antonio Texas. I have a 1950 1/2 ton that is still all original that serves me well hauling stuff & doing chores around the place.

Are your front wheels 6 lug? If so you should look for 6 lug rear axle unless you want to carry two different spare tires.
With a TH350 (no overdrive) and stock sized tires, you will want something like a 3.08 to 1 gears if you want to cruise at highway speeds. You won't win any drag races, but you won't have to stop at every gas station either.
Carl

I run a 3.07 Spicer from a '59 GMC (6 lug) in my '56 with 350/400. I wouldn't want it any lower. In fact it could stand to be a little higher.

Some specifics to help spur some more conversation & advice........
I will be installing a modern IFS which will be 5-lug. Don't want 2 different spares, so the rear end should be 5-lug as well. Hopefully someone can recommend a link to an article that describes the best or easiest choices for a drive train swap for our AD trucks so I can begin my junkyard search, be it from a car or a truck.

Thanks!

WELL YOU DID A POOR JOB ON SEARCHING



- - - - - - - - - >>>> the word BEST is best for who ??
a broad term like ...........'' IF ''


Suspension Measurements

REAR SUSPENSION:
The following is a general list of rear ends and their dimensions to help narrow the search for a possible candidate to replace the torque tube rear end or just get a better set of gears for highway driving.
Advance Design Trucks seem to be using rear ends with widths ranging from 58"- 62". I'm not sure of the Task Force width ranges at this time.
Contributing information were Bob Welch, J Forbes and various locations throughout the Web and Automotive Magazines.
Rear Axle Measurements
MEASURED ACROSS WHEEL MOUNTING SURFACE
56 1/2" 71-77 Ford Maverick 8",
57" 71-74 V-8 Mavericks 8", All '75-77 6's & 8's Maverick 5 Lug 8", 49-51 Ford, 57-59 Ford 9"
57 1/4" 64 1/2 - 65 Mustang
58" 78-88 Mid sized GM Car, Malibu/Monte Carlo (82 up Metric Studs), 80 Granada & Lincoln Versailles,
67-70 Mustang/Cougar/Fairlane, Regal with 10 bolt axle, S-10 P.U., 65-67 Nova
58 1/2 " Ford Grenada
59" 68-83 Corvette
60" 55-64 Chevy Car, 67-69 Camaro, 64-67 Chevelle, 68-74 Nova, 71-73 Mustang/Cougar, 84-95 Corvette
60-61" 64-69 1/2 ton 2wd Chevy/ Some GMC 6 lug rear end 12 bolt Coil spring set up Possible gear ratio's 3.70
62" 64-77 Chevelle, 73-76 Torino, 89 Trans Am,
70 2wd 6 lug rear end 12 bolt Possible gear ratio's 3:08, 3:40, 3:73
70-81 4wd 6 lug reared ...............................................................
71- Newer 2wd trucks use a 5 on 5 lug pattern
71-76 Full Size Cars " "" "" "
60" 60's GMC and some Chevy's Dana 44 or Dana 60 with leaf springs 6 lug, Gear ratio's 3.21 to 3.92. GMC V-6 used a 3.21 Dana 44 used a standard chevy 1310 yoke, Dana 60 used the heavy duty yoke which takes the larger 1350 yoke.

Approximate rear end widths measured from backing plate to backing plate.
Add Width to compensate for drums as follows:
4" - 5" for small cars 5" - 6" for intermediate cars 6" - 8" for large cars
48" - 49" 50" - 51" 52" - 53"
'71 Colt
'72 Cricket
'72-75 Datsun Pickup
'72-73 Mazda '65 Ram American
'74 Valiant '28-40 Ford , '57 - 59 Ford
'62 Buick Skylark, '67 Chevrolet Six
'67 Mustang Six , '68 AMX
'69 Javelin Six , '70 dodge
'70 Duster , '71-77 Maverick
'71 Comet , '71- 72 Pinto
54" -55" 56" -57" 58" - 59"
'39 -48 Chevrolet, '68 GTO
'41 -48 Ford, '68-72 Chevelle
'55 -57 Chevrolet, 68-69 Fair lane 6 or 8
'66 Falcon, '69 Chevrolet
'67 Mustang V-8, '69 Firebird
'69 Cougar, '71 -73 Nova
'73 Ventura, '73 Mustang '36 Plymouth, '54-56 Ford Pickup
'67 Lincoln, '69 Dodge
'69 Dodge Van, '71 Torino
'72 Cougar, '74 Pontiac '49 Plymouth, '61 Chevrolet Impala
'65 Cadillac, '66 Buick Wildcat
'66-67 Chevrolet Big Car, '72 Charger
'69 Oldsmobile 88, '72 Chrysler
'72-73 Torino

STOCK CENTER TO CENTER SPRING PERCH DISTANCE
25" 39" 42" 42 1/2
'68 - 72 Chevelle '71 Colt
'73 Mazda '68 -71 Fairlane/Torino
'49-51 Ford '69 Chevrolet
'69 Nova
'71 - 72 Pinto
'73 Ventura
43" 43 1/2" 44" 46 1/4"
'65 Ram American
'64 1/2-'65 Mustang
'67 Mustang
'70's Ford Grenada
'69 Firebird
'70 Dodge '71-77 Maverick
'70 Duster
'70 Nova
'71 Comet
'72 Dart
'72 Cougar
'74 Valiant '57 Ford
'67 Chevrolet Six
'68 AMX
'69 Javelin Six '69 Dodge
47 1/2" 48" 51" 57 1/2"
'39 -48 Chevrolet
'67 Chevrolet big car
'72 Charger
'72 Chrysler '69 Dodge Van
'69 Ford Van '67 Lincoln

BACK TO TOP OF PAGE

________________________________________
The following list of extensive information was contributed by R. Welch:

Original Vehicles
Rear Suspension Width (Flange to Flange)
Year Classic Vehicles Width
26-39 Plymouth-Dodge car/pick up 56-58"
40-52 Plymouth-Dodge car 60-62"
26-39 Chrysler/DeSoto Car 60"
Most Early Mopar's 56-62"
25-39 Chevy Car 56-58"
26-46 Chevy Truck 56-58"
40-48 Chevy Car 58-60"
49-54 Chevy Car 58-60"
47-54 & 55 1st Series Chevy Truck 60-62"
Most Early Buick,Olds, Pontiac 58-61"
28-31 Ford Car/Pickup 57 1/2"
32 & 33-34 Ford Car/Pickup 56 1/2"
35-48 Ford Car 57-60"
35-41 Ford Pickup 56-60"
49-58 Ford Car 57-58"
49-56 Mercury 57-58"
49-51 Mercury 61"
64 Falcon 58"
67 Cougar 60"
55-59 Chevy Pickup 62"


Donor Vehicles Front and Rear
Suspension Width (Flange to Flange)
Year Classic Vehicles Width Front Width Rear
74-79 Ford Mustang II/Pinto & Mercury Capri/Bobcat 55 ½" 55 ½"
71-77 Ford Maverick with 8" axle 56 ½"
75-80 Ford Granada with 8" axle 57 ½"
64-66 Mustang 57"
67-71 Mustang 59"
72-73 Mustang 60"
67-69 , & 60" Camaro 60"
64-67 Chevelle 60"
55-64 Chevy car 60"
65-67 Nova 58"
68-72 Nova 60" 60"
78 & up Monte Carlo, Regal, etc. with 10 bolt axle 58" 58"
68-72 Chevelle with 10 bolt axle 61 ½"
89 Trans AM (Disc brake) 62"
76-80 Camaro/Firebird 61 ½" 60 ½"
68-83 Corvette 58 ½" 59 ½"
84-95 Corvette 59 ½" 60 ½"
Early 70's "A" body (Dart/Duster) with V8&3/4 axle 58"
"E" Body (Cuda) with V8&3/4 axle 58"
Dodge Dart 59" 55 ½"
Plymouth Volare & Dodge Aspen 61" 60 ½"
71 Blazer (6 lug) 63 ¾"
75-78 Granada 9" (43" perch to perch) 52 ¼"
75-78 Maverick 9" (43" perch to perch) 56 ¼"
81-87 Olds Cutlass 58 ½"


________________________________________

FRONT SUSPENSION INFORMATION

Track Width of Popular Donor Car Clips
Manufacture Model Years Track Front/Rear Curb Weight
Chevrolet Nova 68-74 59.8-59.6 3,770
Buick Apollo 68-74 59.1-58.8 3760
Pontiac GTO 68-74 59.9-59.6 3880
Chevrolet Corvette 68-83 58.7-59.5 3655
84-95 59.6-60.4 3890
Chevrolet Camaro (Z28) 76-80 61.3-60.5 3820
Pontiac Firebird (TA) 76-80 61.3-60.5 3900
Ford Mustang II 74-79 55.6-55.8 3305
Pinto 74-79 55.6-55.8 3305
Mercury Capri 74-79 55.6-55.8 3305
Bobcat 74-79 55.6-55.8 3305
Chevrolet Monte Carlo 78-86 58.5-58.8 3235
Buick Century 78-86 59.0-58.8 3700
Pontiac Grand Prix 78-86 58.9-59.0 3735
Plymouth Volare 75-79 61.0-60.5 3395
Dodge Aspen 75-79 61.0-60.5 3395
Dodge Dart 76 59.2-55.6 3600

Table taken from "How to Build a Custom Classic Truck" Peterson Publication; June or July 1999
Written by: Don Emmons & Mike Briggs

the rear end in my 1951 3104 1/2 T is a 1978 4x4
all hangers removed spaced back by 3''

here is how that is done
http://s67.photobucket.com/user/1951otter/media/Scan1_0001-1.jpg.html?sort=6&o=336

a centered wheel

http://s67.photobucket.com/user/1951otter/media/587685-R1-048-22A.jpg.html?sort=6&o=284

http://s67.photobucket.com/user/1951otter/media/0035595-R1-014-5A.jpg.html?sort=6&o=6

1951 Delux Chevrolet 5 Window Pickup
Tire Diameter : 28 inches

Rear Gear Ratio 2: 3.40:1
MPH @ 3:40 ring & pinion
RPM 1st 2nd 3rd 4th 5th 6th
1000 8 12 18 24 32 0
1500 12 18 26 35 48 0
2000 16 24 35 47 64 0
2500 20 30 44 59 79 0
3000 24 36 53 71 95 0
3500 28 42 61 82 111 0
4000 32 48 70 94 127 0
4500 36 55 79 106 143 0
5000 40 61 88 118 159 0
5500 44 67 97 129 175 0
6000 48 73 105 141 191 0
6500 52 79 114 153 207 0
7000 56 85 123 165 222 0
7500 60 91 132 176 238 0
8000 64 97 140 188 254 0


MPH @ 3:43 ring & pinion
RPM 1st 2nd 3rd 4th 5th 6th
1000 8 12 18 24 32 0
1500 12 18 27 36 48 0
2000 16 24 35 47 64 0
2500 20 31 44 59 80 0
3000 24 37 53 71 96 0
3500 28 43 62 83 112 0
4000 32 49 71 95 128 0
4500 36 55 80 107 144 0
5000 40 61 89 119 160 0
5500 44 67 97 131 176 0






1951 Delux Chevrolet 5 Window Pickup
Tire Diameter : 28 inches

MPH @ 3:73 ring & pinion
RPM 1st 2nd 3rd 4th 5th 6th
1000 7 11 16 22 29 0
1500 11 17 24 33 44 0
2000 15 22 33 44 59 0
2500 18 28 41 55 74 0
3000 22 34 49 65 88 0
3500 26 39 57 76 103 0
4000 30 45 65 87 118 0
4500 33 51 73 98 133 0
5000 37 56 81 109 147 0
5500 41 62 90 120 162 0







MPH @ 4:11 ring & pinion
RPM 1st 2nd 3rd 4th 5th 6th
1000 7 10 15 20 27 0
1500 10 15 22 30 40 0
2000 13 20 30 40 54 0
2500 17 26 37 50 67 0
3000 20 31 44 59 80 0
3500 23 36 52 69 94 0
4000 27 41 59 79 107 0
4500 30 46 67 89 120 0
5000 34 51 74 99 134 0
5500 37 56 81 109 147 0

Thanks for all the info Jim. LOTS of choices! I'll figure it out on my own.

When measuring the width of my trucks rear axle do you measure distance from backplate to backplate or outside of brake drum to outside of brake drum? Still trying to find a good replacement rear to upgrade my original with.

Thanks!

My first project I placed a firebird rear in my 1950 1/2 ton with 3.41 gears along with a 350:400 combo.During final frame mockup (I never finished this one...:( See the gallery!) it fit quite well. However with 235 tires on the back it was so close to rubbing the inner bed side. I can't remember what its width was. I believe it was about a 78 firebird. Somewhere in there. Crazy how fast 15 years can go, eh?!
I would definitely measure both back to back and front to front and also have an idea of what size tires and wheels you want to run.
It is frustrating doing this as so many factors come into play. I wanted the same thing (still do some times)... I just need someone to tell me what to do! Good luck Spotbiltxo!

Lots of great info here. Im in the process of putting a new rear end under my 3600 but am wanting to go with a 6 lug instead of the HD 8 lug.

Thanks for the comment Fox. I guess the secret is finding a modern donor that's as close to the originals width as possible. I'll measure & head out on a junk yard search mission!

I just finished a RE swap in my '52 3100 5 window. I used a '71 Nova RE. The width was perfect. The spring perches and shock mounts had to be fabricated but that was no big deal. While I was at it, I converted it to a posi and paired it with a T5 tranny. Now I'm cruising in 5th gear at 70 mph effortlessly.

What year and model of vehicle is your T5 from?

I used an early nova rear end in mine 1976 I believe, mounting/spring track is the same, left about a 1/2 inch gap on either side of the springs while sitting in the perch, removed smallest spring to fit depth of spring perch, cost at the time 150.00 and I had to remove it. Also used relocating blocks to kick rear end back about an inch to center wheels in well, needed longer u-bolts, purchased at any autozone or who ever is in your area

you need to measure WMS to WMS (WMS = Wheel mounting surface). Some backing plates are dished, some are almost flat, brake drums can be different widths so, the real measurement you want is WMS to WMS. Depending on what you are doing with the truck, you may want it wider or narrower than stock. If you want normal truck tires, same size all the way around, you want the rear end real close to the same width as the front, if you want huge hotrod tires on the rear and deep dish wheels, then you might want the rear a bit narrower than stock...

Excellent advice Mike! I always assumed that you should measure from WMS to WMS, but seems everyone always recommends measuring back-plate to back-plate.

Thanks for clearing it up for me.

Chuck