Does this axle interchange with any cars especially 71/79 b bodies?

The truck unit is 1-3/8" wider than the 71-4 B unit.

The 72-74 2wd truck 8 3/4 is basically the same axle assembly as the 70-74 C Body except the spring perches are welded on the opposite side and are A Body width also there is a difference between 72-74 2wd and 4wd truck axle assemblies, the 2wd has the common 4.5" bolt pattern the same as the dodge cars and the 4wd axle assembly has the 5.5" bolt pattern which common with some of the Ford trucks in the day. They are pretty wide axle assemblies for most of the B bodies.

I've had several 72-78 W100/150 and mine were all 4.5 bolt circle.

weren't the trucks with automatic hubs the 4 1/2" bolt pattern ?

I had both autos and 4-spd with 4.5 bc.
I thought the larger bc was in the 80's.
I've had a gazillion 72-80 trucks of all sorts and none were the larger bc. I've never messed with the 81-up other than my 92 1-ton.

up through 74 all w-100 were 5 on 5 1/2
75-79 w-100, w-150 were 5 on 4 1/2
80 on up w-150 were 5 on 5 1/2
Ramcharger/Trailduster 74 -79 5 on 4 1/2
Ramcharger/Trailduster 80 on 5 on 5 1/2

I just parted out a 73 W100 and am using the 8.75 in my 78 D100. It is 4.5 bc.

Had a 74 pickup with 8-1/4 that had a bad axel, took a 8-3/4 out from under a 69 Fury. Knocked the perches of with a big hammer laid em on top then tightened up u-bolts. Got er lined up and welded where they sat. No problems. Can’t remember about the e brake cables.

Unless its from a '71-up B-body wagon which uses the same width rear as a C.

Correct which is also the same width as the truck unit.

73 4x4 is 5 1/2. 2wd is 4 1/2. If you had a 4 1/2 in a 73 4x4 some one put it there. You can not put a 4 1/2 on a front with locking hubs. If you do have a 4 1/2 front it is full time and again not correct for a 1973.

Here is what a factory 72-74 W-100 Power Wagon wheels look like. 5 on 5 1/2.

agree. locking hubs = 5x5 1/2" bc.
non-locking/"automatic"/full time 4x4 = 5x4 1/2" bc.

I can confirm that at least a 1974 4x4 Dodge 8-3/4 bolt pattern is 5x5.5". Pulled one from a truck in Yuma back in January. Had a 489 case and I traded it off for a car transport. Kicking myself for that one.

Well alrighty then. The 73 I just parted was missing the front axle when I got it so someone maybe changed out the rear. At one time I had probably around 10 truck 8.75 rears and all had 4.5 bc axles.
Love learning new stuff.

for my trucks I have found that they all will fit a truck with a little effort.

the truck housing is 59" flange to flange 43" perch centers for axle under spring. it came with 5 on 4.5 & 5 on 5.5

my 74 w100 had 59" housing 489-3.91 cone suregrip. 5 on 5.5 with 43" perch centers axle under spring

my 74 Chrysler Newport 8 3/4 is also 59" flange to flange 489-3.23 5 on 4.5

any of the 73-74 c-body 8 3/4 housings will replace a truck housing with perch change and axle interchange for wbp size 5 on 4.5 or 5 on 5.5

FYI..

A-body 8 3/4 shares same 43" perch centers for axle over spring

I also tub & lower all of my trucks using different 8 3/4 housings to fit my needs.

A-body housing with Moser large brake offset axles 5 on 4.5 12" rim 4.5 backspace 29x15x15 under my 88-440 truck with a rear shackle flip axle on top of spring

67-C-body/E-body housing 55.5" flange to flange/stock axle 12" rim 6" backspace under my 85 step side 318 truck with shackle flip axle on top of spring

I just picked up a 70 B-body 8 3/4 to use under my 86 w150 build.

It blew my mind when I found out with that last 8-3/4 I pulled. I was thinking someone had the axles custom built at some point but I googled it.

in 85 all the 2x trucks went 5 on 5.5 with the 10 bolt 8 1/4 and 12 bolt 9 1/4 axles being 5 on 5.5 and IIRC the axles do not interchange due to carrier side gears/spider gears.

76 new Yorker front rotors will work on the 82-84 2x truck spindles & 85-93 2x truck spindles when swapping down to 5 on 4.5 to match a 8 3/4 5 on 4.5