Narrowing Model 20 Differential

It depends on how original you want your rear to look. Cutting the bearing ends and replacing with a better option like Ford, and obtaining solid axles would make it easier, but still will need to have alignment done when installing the ends.

matty 401 wrote: doctor diff has one piece axles  my son is running them in his Hornet hatchback

So axles wouldn't be a problem.

Rebel Machine wrote: Keep in mind the big body cars use coil springs and the smaller body cars use leafs.

Aaah.  So you'd be better off starting with an AMX/Javelin rear so you had the spring perches.  Good point.

Why would you put Ford ends on a AMC axle?   Ditch the 20 and get a currie 9...Way more options built any way you want.

I had the original AMC 20 rear narrowed in our 67 American for more tire clearance and used Ford bearing ends. It frees you up to use common axles, bearings and seals. Prior to this I used Mosure one piece AMC axles and IIRC they used an uncommon sealed "green bearing" that sealed with a bead of silicone and I always had trouble with it leaking. The other advantage to the ford axle flanges is you can use any common rear disc brake kit. There are a couple of Ford flange styles, but I used the one that accepted the common Ford Motorsport Explorer disc kit with the internal parking brake.

The set up worked great except the guy that narrowed it screwed up the carrier bearing alignment and it would wear the carrier bearings oval in 100 miles.

Now I have a 9" Ford out of a truck and I wish I didn't. It weighs a ton, It's hard to get gears that are quiet, It's less efficient and the rear of the housing is so deep, it moves the rear wheels forward to clear the gas tank and it's expensive. I wish I stayed with the AMC or maybe a Chrysler 8-3/4 or Ford 8.8.