I have a 71 dart that I'm going to put an 8.75 rear end into. I know where I can pick up an original A body 8.75 housing but I'd have to buy new axles and brakes to convert to the BBP. Which would cost more. Or, I could get a rear out of a 66-67 b body with the BBP axles, brakes and all. Now my main question is that since the rear end is 2" wider on the b body would I run into problems finding wheels with the proper backspace? Where would I find the offset shackles to make the sprong perches line up if I drcidr to use them? Should I fool with the b body rear or spend the extra on the A body?

The axel perches are .25 off on each side the springs can be squeezed to fit it wouldn't need shackles. The wheels would need to have a 5.25" or 5.5" backspace.

I had a 66-67 b-body rear cut to the a-body dimensions. I ended up buying new axles, but you can have original axles cut and resplined. I also had the spring pads moved inward to the a-body width.

I looked at buying a factory a-body 8-3/4, but guys want a ton of money ($400.00+) for a used one in need of a total rebuild. I was not in love with the small bolt pattern and smallish brakes and would have switched them over which equals even more money yet. I was given the b-body housing for free so all I paid for was to have it cut down and have the pads moved. The price was a little over $200.00 to have the housing work done. The axles were $325.00 from Dutchman.

If you want the small bolt pattern and can find a good a-body rear for a fair price then go for it. I wanted the large bolt pattern so it didn't make sense to pay a premium for a semi-rare a-body axle and then discard half the parts.

The perches are actually .50 inches wider on each side. Not a big deal to pull the springs out.

If you use a 66-67 B rear, the wheels need an additional 1 3/16" more backspace to sit in the same place as with an A body 8.75"

68-70 rear requires 1 1/2" more backspace.

Move the spring perches. You'll lose 1/2" of spring to tire clearanxe if you don't, besides your car will look like doodoo from behind. do it the right way.

I can get the A-body housing for 250 and the guy will probably throw in the 11" BBP brake hardware I'll need and a pegleg pumpkin. I also found a supplier on ebay that sells Yukon axles a body width for 169 a set with no bearings. I know it will be less money for the B body rear set up but I think that for the extra few hundred it would be worth it for the stronger axles and have the deeper dish wheels. Thanks for all of the help.

Be careful with those off the shelf Yukon axles. They are too short to be used in an original housing with with a vintage clutch sure-grip.

So, what would I need to do to make the axles work? Would I need an aftermarket sure grip clutch assembly, or spool? I am planning on running a single trac rear for now while I piece everything together then upgrade to sure grip. The description says the axles are 28" what length would I need for the stock sure grip?

Yukon A-body axles are actually 27.875" long. This does not provide enough spline engagement for early clutch sure-grips with 2 piece side gears. You need axles that are made to the correct length, or a NEW sure-grip with 1 piece side gears.

BTW, I stock new clutch sure-grips, correct length axles, powder-coated, bolt-in A-body 8 3/4" housings, drum and disc brakes and just about anything else you can think of for 8 3/4" and Dana 60 rears.

Just FYI I bought the yukon axles from that guy on ebay. I have had no problems. He also has the brake package you need with shoes,hardware,cylinders,drums,backing plates ect. It went in my car smoothly. Tod

I sold at least as many Yukon A-body axles as ANY other Yukon dealer. Ever since I bought the first batch about 8 years ago, I have been trying to get the manufacturer to make the axles the correct length for use with ALL sure-grips.

I quit selling those axles a couple years ago because I got tired of asking everyone what type of sure-grip they are running. Most people don't even know without checking. I also did not like having to warranty stripped axles because the inner side gear only had 1/8" of spline engagement.

Judging by their latest website ad, Mancini Racing must have finally realized the problem with the axles, because the customer must now specify their diffential type when ordering.

The best part is, I now offer completely assembled, CUSTOM LENGTH, 30 AND 35 spline axle packages machined specifically for the application (by me) for about the same price as partially assembled off the shelf stuff.

Wow! Thanks Dr. Diff for the info. I am not even sure if I have a sure grip. I bought the rear used. I know some times I get a one wheel peel and if I power brake it and take off I get two black marks. Sounds like a sure grip? If so what do I need to do to make sure I am ok. I wish I could have found you about a month ago.

Sounds like you have a worn out cone sure-grip. It has 2 piece side gears, but because they are farther apart internally, they work OK with the shorter axles.

The only differential that doesn't work with Yukon axles is a vintage clutch type (power-lock) sure-grip. Unfortunately, those are the most sought after used units.

I have not driven this car yet on the open road. I guess I could turn the rear yoke and see how much play is there. Couldnt I? I mean how long it takes the wheels to turn versus turning the yoke. How much would a reman unit cost me? Tod

If you can see coil springs through a window in the carrier, and the case-half bolts are located on the ring gear side, you have a cone sure-grip. I charge $50 to remachine and shim that unit.

If the carrier is really solid looking and the case-half bolts are opposite the ring gear side, you have a clutch sure-grip. I charge $275 to install all new internals with 1 piece side gears in those.

As soon as I get my ducks in a row I will get in touch with you. Thanks for the time and great info. Tod