identafing a-body 8 3/4

[crashing513]

what do i look for to id an a-body 8 3/4 rear axle,measure between perches?

[Ray Bell]

Yes, 43" from centre to centre...

You also can measure overall length. Unfortunately the diagram that was available here isn't any more, but even so, that didn't give you a dimension over the brake drums or axle flanges, which is the easiest to measure.

A-body is 57⅛"... nothing else apart from pre-64 stuff comes close to that measurement so it's easy.

Most A-body stuff has the smaller 4" stud circle too. You're really lucky if you find a late model one with the 4½" pattern.

[JVMopar]

Somewhere on one of my computers I have that diagram saves....... I think.

Found it

[Ray Bell]

Yeah, that's the crazy idea someone had...

Like I said, the easiest dimension to take is over the whole assembly, from wheel mount face to wheel mount face. Because the different models have different distances from the axle housing flange to the axle shaft flange, you can make mistakes.

Just to give you an idea, check this:
Model . . . . . . . . Overall width . . . Housing width . . . Perches
1966-'72 A-bodies 57⅛" . . . . . . . . 53.2" . . . . . . . . . 43.02"
1962-'63 B-bodies 58½" . . . . . . . . 53¼" . . . . . . . . . 44"
1964-'67 B-bodies 59½" . . . . . . . . 54¼" . . . . . . . . . 44"
1970-'71 Imperial 59¾". . . . . . . . . 54¾" . . . . . . . . . 46"
1968-'70 B-bodies 60⅛" . . . . . . . . 54.937". . . . . . . . 44"
1970-'74 E-bodies 61⅝" . . . . . . . . 56.484". . . . . . . . 46"
1965-'69 C-bodies 61¾" . . . . . . . . 56¾" . . . . . . . . . 46"

1965-'66 Imperial 62" . . . . . . . . . . 57"
1967-'69 Imperial 62.3125". . . . . . . 57⅜"
1970-'71 C-bodies 63" .. . . . . . . . . 57⅞" . . . . . . . . . 46"
1971-'74 B-Bodies 63" . . .. . . . . . . 57.8" . . . . . . . . . 47.3"
1971-'73 B-Body wagons 64⅜" . . . . 59.438" . . . . . . . 47.3"
1969 C-body wagons 64⅜". . . . . . . 59.438" . . . . . . . 46"
1970-'73 C-bodies 64⅜". . . . . . . . . 59.438" . . . . . . . 46"
1965-'70 A100 vans 61¾". . . . . . . . 56¾"
1965-'71 D100 trucks 64". . . . . . . . 58.313"
1972-'74 D100 pickups 64⅜". . . . . . 59.438"

I would reckon some of those measurements were taken by different people with different standards, but it's all probably close enough. The models missing from this list, which are in the chart above, are:

1973-'76 A-body
All F-body
1970-'71 Imperial
1972-'73 Imperial
1964 Max Wedge
1970-'71 Chrysler and Fury

It would be good to know, and probably not hard to find out, the perch distance for the commercial vehicles.

[peg leg]

Came from hemmings motor news website. It is complete and accurate. Every dimension known to man!

[Ray Bell]

Certainly the dimensions I added in above were from Hemmings... but there are some missing, as I've noted...

What is good is that it's the overall width dimension that's given. Spring perch dimensions would be handy, but for a quick measure-up the overall figure is the one that works.

Ever tried to get a tape measure into the recess where the backing plate comes over the end of the axle housing?

[John Kunkel]

Every 8 3/4" rear end spec chart that I've seen that has a graphic in it is horribly wrong. Most use Mopar dimensions that are for the wheel track, not the actual rear dimensions.

The correct dimensions are here:

http://www.moparts.org/Tech/Archive/axle/16.html

[crashing513]

do they most of the time have some nice jucie gears in them

[crashing513]

have a guy who says hes got one with new mosier axles+bearings $450 good deal?

[dave5711]

i'd say that's a good deal. Teh axles are worth 300 alone aren't they?

There is mention above of finding a later one with 4.5" axles. There is no such thing from the factory. Does not exist.
ALL a body 8.75's were small bolt, and subsequently all small bolt 8.75's were for a body cars.

The ones that are big bolt now, are ones that have had a conversion axle installed in them, or been redrilled. Conversion axles are generally an off the shelf item from an axle supplier.

The big bolt performance A body cars in the later years, had 8 1/4's in them.

[Ray Bell]

Originally posted by John Kunkel
Every 8¾" rear end spec chart that I've seen that has a graphic in it is horribly wrong. Most use Mopar dimensions that are for the wheel track, not the actual rear dimensions.

The correct dimensions are here:

http://www.moparts.org/Tech/Archive/axle/16.html

Yes, that's another useless statistic...

Track would obviously depend on what wheels were fitted. That's a good one, John, but it needs putting into chart form.

And it still misses out on giving the specs for the pre-62 models. They'd be very handy to have.

[John Kunkel]

For pre-'62 8 3/4" housing and overall width specs you need look no further than the '64 B body, all specs are the same except for the spring pad width which is 46" on the Forward Look cars. (same as the C and E body)

[crashing513]

so the really nice thrust 2s rims i got 5 4 1/2 rims will not fit a true stock a-body 8 3/4?

[crashing513]

turns out its a shure grip out of a 69 imperal with no perches

[Ray Bell]

A bit wide for an A-body...

Do the imperials have coil springs or something?

[ehostler]

The graphic above is incorrect. I corrected it at a later date, with accurate information. It was posted in the archives. Since the board update, the old attachments no longer work. I may have a copy of the accurate data still.

[ehostler]

Here is the corrected one.

[John Kunkel]

That graphic still has inaccurate '64 B body housing width info, see the data on the Moparts link.

Also, I believe that the drum-to-drum dimension is the most important when assessing fitment in different bodies, most graphics don't have that dimension or have inaccurate dimensions. (track width)

[ehostler]

Well John, the numbers were only as accurate as my source. In this case, the source was you. You provided me with all of the data and then reviewed it, before I finalized the picture. Now, 6 years later, you are telling me that it is inaccurate.

Also, 6 years ago, you told me not to use the track number as it can be confusing. Now you are saying that its the most important number.

[Ray Bell]

Drum to drum is the one that really counts...

[John Kunkel]

Originally Posted by ehostler

Well John, the numbers were only as accurate as my source. In this case, the source was you. You provided me with all of the data and then reviewed it, before I finalized the picture. Now, 6 years later, you are telling me that it is inaccurate.

Yep, I was wrong and amended the info on the Moparts site.

Also, 6 years ago, you told me not to use the track number as it can be confusing. Now you are saying that its the most important number.

No, my contention then and now is that the track info listed in many graphics is totally useless but the drum-to-drum dimension is very important and it's lacking in most, if not all graphics.

[crashing513]

thanks for all the info correct or non correct.think im going to stay with factory for now. going to get it road worthy first before i start tweaking. any body have a link or site to get a replac ment rear harness . my light plugs are gone.