Does anyone know if a Chrysler 8 3/4 rear will fit an F-body

[2002ssslp]

I have been looking for a good replacement for my weak 10 bolt, 7.5" rear in my modded 02 SS. I like the Strange and Mosier products but they cost big bucks. I really like the Ford 9" because it is super strong and it is easy to change gears and axles just by pulling out the chunk.
I am an old Mopar guy and I have delt with Dana 60 and Chrysler 8 3/4" rears for 35 years. While I do not have any Dana's left I do have 2 8 3/4 rears in the garage. They have been used in Hemi vehicles with auto transmissions so I know they will not break. They also have the same design as the Ford 9" with a center section without C clips. Has anyone tried to put this rear in an F-body. I am looking to put it in my 02 SS.

[justinmc978]

never heard of it, sounds like a cool project.

[pajeff02]

Anything is possible. First step would be to get some measurements for comparison. You'll need a donor axle to lop off the spring, shock, control arm and panhard bar mounts, or you will have to fab your own. Biggest challenge will be the torque arm mount -- I would fab a bolt on mount that attaches to the face of the carrier. Lots and lots of work that will require precise measuring and considerable skill.

[Firebirdjones]

I've adapted plenty of the 9" housings to 3rd and 4th gens. Very easy since Currie makes a bolt on torque arm mount, and they sell all the necessary weld on brackets. I just narrow the housing and axles, set it up and it's good to go. Much cheaper than buying a complete drop in unit.

Since the Chrysler 8 3/4 is manufactured similar to a 9" (drop out 3rd member) then a bolt on torque mount is possible (actually easier to fab than conventional rears).
Unfortunately nobody makes one to fit the chrysler 8 3/4. I'm willing to bet though, that you could start with Curries 9" torque arm mount and modify it to work on the 8 3/4. Once that hurdle is accomplished, the rest is easy. Narrow the rear and axles to the required length and weld on your brackets.

Your only hang up would be checking with the aftermarket for disc brake conversion kits on the 8 3/4. Since this isn't a common swap rearend (even for street rods) your choices are limited.
Disc brakes for the 9" housings are easy and sold everywhere. 9" has huge aftermarket support.

[2002ssslp]

I wonder why no one has done this swap before. The Chrysler 8.75" rear is super tuff and it ran in production for 30 years or more with the latest run having a 1 7/8" pinion along with an 8 3/4" ring gear and 1350 Spicer joints this rear was an animal. That being said it was also used in just about every V-8 vehicle built by Chrysler and AMC. Thousands of these rears exist in boneyards around the country. Somebody please start looking into this opportunity. A young guy with a few bucks and a welding set may be able to make some big coin out of this deal. I wonder if this is how Strange and Mosier started out.

[Firebirdjones]

The biggest reason I see, is that no one makes a torque arm bracket that is readily available. Like I mentioned, Currie offers the 9" torque arm bracket, and it's possible that it could be made to fit with some grinding/cutting and fab skills. But it's alot of effort to use an 8 3/4 chrysler rear when there are so many 9" rears to choose from. The 8 3/4 hasn't been produced since 1974, so the bone yards are thin.

Plus the fact that the 1.75 inch large 10 spline pinion you speak of is only found in the desirable and hard to find #742 3rd member (big $$$ to collectors). The larger 1.88 pinion (10 or 29 spline) is only found in the #489 3rd member and that pinion is tapered.
The more common #741 3rd member you find only has the 1.38" pinion. That will snap like a twig.

So for any real good 8 3/4 chrysler rear parts, you pretty much have to go aftermarket now. The housings are reproduced by Moser, Mopar Performance sells the aluminum 3rd members that are stronger, and axle shafts are made by Yukon and Strange. By the time you price all that out, the drop in units from Strange are about the same price.
Any decent 8 3/4 rear with a 742 3rd member is probably worth more to someone restoring a numbers matching car.

9" rears are still a dime a dozen and were produced up to 1986. Still in the bone yards. Forget searching for the highly sought after "N" case. Those fetch $6-$800 with the right date code. Strange makes a nice affordable 3rd member to start with and it's much stronger than the "N" case anyway.
Disc brakes are easy to adapt, and parts are cheap. Currie makes the torque arm bracket as well as control arm and panhard brackets.
For roughly $1500-$2,000 you can narrow a housing, new axles, new Strange 3rd member, new gears and setup kit, all your brackets needed etc....you just need some fab skills and a welder.

In the end it only saves you about ~$500 from a drop in unit bought through Strange or Moser.

Yes you can make money at it, I did for years doing 9" housings for 3rd gens long before anyone made a drop in unit so the concept is nothing new. But like I said, it was still $1500-$2,000 to do it all, and do it right with all brand new parts. More could be saved if someone had good used 3rd members laying around, but even those are a crap shoot (good ones are drying up). Most of them needed the posi's rebuilt anyway at a minimum. Most of them I take apart have the rear pinion bearing support casting broken on the inside which makes the 3rd member nothing but a door stop. Starting with a new Strange 3rd member is the best bet for about $400

[2002ssslp]

Well, there goes that idea.

[Firebirdjones]

I didn't mean to rain on your parade. Those are just the reasons why I believe you don't see it done.
The 9" simply became the rearend to swap in everything from street rods to muscle cars, to off roading etc...so the aftermarket is a huge support. Really makes it easy to do.