Pros and cons of using a B-body rear axle assembly???

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MRGTX

MRGTX

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It sounds like lots of guys use B Body rear axle assemblies for a number of obvious reasons, primarily that they're more plentiful in terms of the stronger units.

It sounds like the only accommodation that has to be made for using them in an A-body is the relocation of the spring perches. Is that right?

The B-Body rear axle is obviously a bit wider than the A-Body unit. To some, this is an improvement because it makes the front and rear track closer to being the same (where stock A-Bodies have a narrower rear track).

Does this impact handling positively or negatively?

Do you think it improves or hurts the aesthetics of an A-Body?

Does this impact tire width options with stock-offset wheels?
 
narrowest b body 8 3/4 rears u could use with the spring perch relocation is 62-64 with brakes that have the nut in the center or 65-67 rear.those are narrowest b-body rears you could use.i put a 65 b-body 8 3/4 under my duster with 15x7 mag rims.you cant even tell,the tires don't stick out or anything.
 
Yes,they work well in the Duster/Demon/Dart Sport body styles. A bit tight in the Valiant or Dart.A friend used a 65 B under his 67 Valiant.Ordered wheels with a 5'' backspace.
 
One thing I would like to add, is that to me personally, I don't like a "flat" looking wheel with no dish. The way the 1/4s are made on a duster or dart sport just look awesome with a wheel with some dish. Not everyone may agree with this, so use your own judgement....
 
I actually used an E body unit (1970 Challenger) in my 1965 four-door Valiant. Made a deal with a fellow Mopar enthusiast to trade an extra A833 four-speed I had in exchange for him flaring out my rear wheel wells. Aesthetically probably not what everyone wants, but in my particular case I think it improved the look of the '65 Valiant (with 4.56 gears it managed a 12.72 @ 108 MPH with the 273 back in the 1970's).
 

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You'll find yourself spending your money on narrowing a rearend with custom axles, or on custom offset wheels. I know someone local that will narrow an 8 3/4 housing for $150, you just have to buy axle. If you go with stock width, lots of axle available for around $300 dollars with new bearings that don't require you to deal with figuring out what to measure for moser or strange(strange is my choice). I narrowed a truck housing. You may not have this option but the stance is better to me. Even with custom offsets, the wheel won't look centered in the tub.
 
I think they are plus IF you are wanting 5x4.5 and 11" drums (as the A-Body housing drum to drum gets wider anyway with this combo) and want to run a more modern rim as they are commonly available in higher offsets.
 
How wide a wheel do you want to run?

I had a bone stock 67 Coronet axle in my 73 Duster.
(no mods, just dropped in with a little nudge)

Looked better with the same track front and rear, and was running 15x6.5 rallye wheels with 225 or 235 width tires.
 
On Dusters, Demons and Dart Sports you will not need custom wheels or to narrow the axle housing if you purchase a 70 and prior B-body axle; it may be the same on A-body Barracudas as well. As for no dish, that would only be if a later than 70 was used. On my Duster I was able to run 10" wide rear wheels with 6.5 backspacing on a stock width B-body Dana. I had similar wheels on my Dart Sport with a stock width B-body 8 3/4. The wheels were not custom; I have seen many sets with that same backspacing at numerous swap meets. Hell, if you decide to get new you can just order them with whatever backspacing you want anyway.

The biggest benefit is if you somehow break an axle shaft, you just go get another; no need to have a custom axle shaft made to fit your custom housing.
 

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Narrowed our rear end big time. Thing is real short now haha
 

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2doorswinger, u made it up in the back spacing and that looks good with a bit of dish...nice
 
Lelo Dart said:
Might as well do it, money spent on custom wheels probably still not as bad as a A body rear end.
Click to expand...

You all making it sound like the 350 bucks I paid at a swap meet for my A body 8.75 with 4.89 3.23 sure grip was a steal back in March 2014
 
MRGTX said:
It sounds like lots of guys use B Body rear axle assemblies for a number of obvious reasons, primarily that they're more plentiful in terms of the stronger units.

It sounds like the only accommodation that has to be made for using them in an A-body is the relocation of the spring perches. Is that right?

The B-Body rear axle is obviously a bit wider than the A-Body unit. To some, this is an improvement because it makes the front and rear track closer to being the same (where stock A-Bodies have a narrower rear track).

Does this impact handling positively or negatively?

Do you think it improves or hurts the aesthetics of an A-Body?

Does this impact tire width options with stock-offset wheels?
Click to expand...

In a Duster/Demon/Dart Sport, it's the way to go.

Increased track width usually increases stability. It may actually hurt handling turn in, but I doubt by much

Improves Aesthetics.

I've run the same offset wheels front and rear with the large bolt 73+ fronts and a 68 b-body rear.

With 275-35-18 F/R on 18x9 +35




Same car, same parts with a 225-60-15 F/R on 15x7 with 4.125 backspace:




And finally, the same car, same wheels with a 1974 8 1/4 a-body axle:




We just put a 65 B-body 8 3/4 in my friend's 71 demon which will have my old 15's...and all you need to do is move the spring pads in 1/2" per side and done. Well, that and swap out the left hand thread wheel studs on the driver's side.
 
I run a 68-70 width B body 8 3/4 rear axle in my Duster, works great. :thumbup:

It really depends on your plans for the rims and tires though. The B body 8 3/4's are perfect in a Duster/Demon/Dart Sport if you're looking at using 17" or 18" rims, because the offset you need to run with those rear axles matches the offsets that are widely available for those rims. No custom rims needed.

You can even still run the stock 15x7" rims that come with a 4.25" backspace, although you'll be limited to a 225/60/15. I ran those on my car after I swapped to the 68-70 B body rear before I went to the 18's I have now.

It's also a perfect time to use a 1/2" spring offset kit, since you'll need to relocate the spring perches on the B body rear axle anyway. B-body spring perches are 44" c-c, A-body spring perches are at 43" c-c. The 1/2" spring offset makes them 42" c-c on an A-body, and with that and a trim on the quarter lip I'm running 295/35/18's on 18x10's with a 7" backspace (+38mm offset) on my Duster. And those rims are right off the shelf, nothing custom.

What the B-body rear ends are NOT good for is running wider 15" rims, like 15x9's or 10's. Those will require custom wheels because the large + offsets that you would need are not available in wider 15" rims sizes. And of course if you want to run a heavily dished rim (negative offset) then the wider rear axle is not a good idea.

My "duster"

IMG_2251_zpslw7ccgzu.jpg


The old 225/60/15's on 15x7" cop rims, compared to the 295/35/18's. Both with the 68-70 B body 8 3/4 and 1/2" offset springs.

tireB-A_zps4efb0119.jpg
 
Just measured the rear that came out of the 69 Fastback
54.25" flange to flange and 44" perch to perch center to center.
65-67 B body 8-3/4. At first I was bummed but now I'm Happy. Think it will work just fine with the 17"x9" -5" BS YO Rallye wheels and the Doctor Diff Spring relocate kit. 275/40-17 should fit just fine.
 
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