B body axle interchange

AMC Diplomat

AMC Diplomat

Well-Known Member
Joined
Feb 14, 2023
Messages
2,016
Reaction score
965
Location
NY
I saw this on marketplace
Screenshot_20260728_074331_Brave.jpg

And I'm wondering if its ALL B body axles that can be made to fit or if its just SOME B body axles from certain years and certain models.

Paging @Aspen500 @BudW @Vaanth @Mikes5thAve @XfbodyX

Help me out here guys before I spend more money on random crap, again
 
'66 to '70 B body axles fit by drilling out the perches to 1 9/16" to accept the larger ISO centering mounts. It's close, but not exact. Your springs will be bowed 1/4" inboard. Many people do this and report no issue. I ran an 8.75" done this way for years. Eventually I did away with the ISO mount and had the perches relocated to correct the minor bow.
 
AMC Diplomat said:
I saw this on marketplace
View attachment 58451

And I'm wondering if its ALL B body axles that can be made to fit or if its just SOME B body axles from certain years and certain models.

Paging @Aspen500 @BudW @Vaanth @Mikes5thAve @XfbodyX

Help me out here guys before I spend more money on r
Click to expand...


The following table lists the B-body 8-3/4" axle dimensions:

Body LineYearsHousing Width
Flange to Flange		Leaf Spring Mount, Center,
Perch to Perch		Drum to Drum, or Axle
Flange to Flange (1)		Axle Shaft Length
(2)		Notes
B-body1962 - 1963,
1964 Max Wedge		53-1/44458-1/230-1/2 with SG
30-7/16 without SG		Tapered axle shafts
B-body1964, except
Max Wedge		55-5/84460-7/831-1/2Tapered axle shafts
B-body1965 - 196754-1/44459-1/228-7/8
B-body1968 - 197054-29/324460-1/829-3/16
B-body1971 - 197457-47/6447-3/106330-5/8
B-body Station
Wagon		1971 - 197359-7/164664-3/831-21/64

Table Notes:
  • (1) Width variance can be drum face thickness.
  • (2) Axle shaft length is measured from the splined end to the outside flange end.
  • SG = Sure Grip
  • Dimensions are in inches.

B-body axles with the 44" perch width are the best candidates for swapping into an F-body with considerations noted in post #2. The F/M/J- body perch width is 44.46". 1962 - 1964 axles require axle shaft replacement to used flanged axle shafts.


Table excerpt from: A Chrysler 8-3/4" Rear Axle Guide, Updated Version
 
Last edited:
Vaanth said:
The following table lists the B-body 8-3/4" axle dimensions:

Body LineYearsHousing Width
Flange to Flange		Leaf Spring Mount, Center,
Perch to Perch		Drum to Drum, or Axle
Flange to Flange (1)		Axle Shaft Length
(2)		Notes
B-body1962 - 1963,
1964 Max Wedge		53-1/44458-1/230-1/2 with SG
30-7/16 without SG		Tapered axle shafts
B-body1964, except
Max Wedge		55-5/84460-7/831-1/2Tapered axle shafts
B-body1965 - 196754-1/44459-1/228-7/8
B-body1968 - 197054-29/324460-1/829-3/16
B-body1971 - 197457-47/6447-3/106330-5/8
B-body Station
Wagon		1971 - 197359-7/164664-3/831-21/64

Table Notes:
  • (1) Width variance can be drum face thickness.
  • (2) Axle shaft length is measured from the splined end to the outside flange end.
  • SG = Sure Grip
  • Dimensions are in inches.

B-body axles with the 44" perch width are the best candidates for swapping into an F-body with considerations noted in post #2. The F/M/J- body perch width is 44.46". 1962 - 1964 axles require axle shaft replacement to used flanged axle shafts.


Table excerpt from: A Chrysler 8-3/4" Rear Axle Guide, Updated Version
Click to expand...
Holy crap what a great answer! Thank you!
 
Not all will fit, overall widith is the other factor but from the charts floating around that one should also be less then an inch wider than typical M body axle so it is the right one to get.

But question is do you really need it? 8 1/4 shouldn't have an issue holding up and 8 3/4 is heavier. On the other hand my philosophy is get stuff when you can cause I know I can't easily find one. Altho price comes in to play with that too.
 
Any of the '65-70 B-body axles will fit fine. The '65-67 is the preferred choice, but '68 works fine.

You also get the Shock Plates, which is a big, correction HUGE, plus.
Toss the original ISO-Clamps (and shocks) in favor of those '68 shock plates.
The B-body shock plates will require you to use '66-72 B-body shocks - in which has a whole lot more choices for (over the lack of FMJ choices). Also, the lower stud on FMJ shocks are a pain to work with.
In my opinion, the older shock plates ride so much better than the ISO shock plates.

If you were to get that setup, I would not save the U-bolts.
Get the measurements off of the old ones and purchase new U-bolts.

Parking brake cables are different - so that will need to be changed.
The 10 inch brake setup should be the same.



If you plan on keeping the original ISO-clamp shock plates (with the older B-body differential), you will need to make the centering hole wider on the differential perches to 1-9/16" (not a fun process, but doable).
I would highly recommend replacing the FMJ U-bolts and shocks, while you are there.

BudW
 
Note: if I was several states closer, I might be interested in getting it.
That said, I already have two '67 B-body 8-3/4" assemblies ( ... and a '66 C-body which i picked up cheap ... ) to go into each of my two cars.

A good thing that one is many many states away.
BudW
 
BudW said:
Note: if I was several states closer, I might be interested in getting it.
That said, I already have two '67 B-body 8-3/4" assemblies ( ... and a '66 C-body which i picked up cheap ... ) to go into each of my two cars.

A good thing that one is many many states away.
BudW
Click to expand...
I don't "need" it, I just replaced the 7 1/4 with an 8 1/4 sure grip last year, this is definitely in the hoarding category

Because hey, what happens when I find another one of these cars that needs an axle?
 
You must log in or register to reply here.
Back
Top