Which differential for a scratchbuild?

[Three Peaks]

The uprights are the part that hold the brake calipers, rotors, and hubs/bearings and connect to the control arms. You'll need them to position your parts, build your control arms and pick up points, and measure the lengths of your axles so you can have them shortened, along with deciding what backspace of wheels you will need or want, where to position your trailing link, and where your shock mounts will be located. They are kind of important at this stage of the build IMO.

As for mounting the differential, I used a 2 x 3 rectangular tube coped to fit the round chassis tubes on each end at the correct height for the differential flange to be located. You need to determine the center line of the axles from the center line of the wheels with the frame at ride height. There will be a lot that will go into this stage of the build compared to the rest of the scratch build. There aren't a lot of blueprints to help you with this part of the build or the uprights you will probably need to build to fit the Tbird/Explorer IRS uprights. You can use original style uprights and adapt them to your differential if you have the ingenuity and ambition. Or, you can get the Jag/Dana 44 type rear and use the same system Kirkham uses with adapters to the stub axles and Porsche 930 axles to go with their machined uprights. Pretty expensive option but plug and play.

Sounds like a fun project. Post pics as you go along- BTW, how far along are you at the moment?

Bob

[120mm]

Originally Posted by Three Peaks

The uprights are the part that hold the brake calipers, rotors, and hubs/bearings and connect to the control arms. You'll need them to position your parts, build your control arms and pick up points, and measure the lengths of your axles so you can have them shortened, along with deciding what backspace of wheels you will need or want, where to position your trailing link, and where your shock mounts will be located. They are kind of important at this stage of the build IMO.

Are they also referred to as "knuckles" or "spindles?" I can't find a picture anywhere of something called an upright, though my plans refer (obliquely) to them. Am assuming they are called spindles or knuckles in other automotive terms.

As for mounting the differential, I used a 2 x 3 rectangular tube coped to fit the round chassis tubes on each end at the correct height for the differential flange to be located. You need to determine the center line of the axles from the center line of the wheels with the frame at ride height. There will be a lot that will go into this stage of the build compared to the rest of the scratch build. There aren't a lot of blueprints to help you with this part of the build or the uprights you will probably need to build to fit the Tbird/Explorer IRS uprights. You can use original style uprights and adapt them to your differential if you have the ingenuity and ambition. Or, you can get the Jag/Dana 44 type rear and use the same system Kirkham uses with adapters to the stub axles and Porsche 930 axles to go with their machined uprights. Pretty expensive option but plug and play.

On the originals with Salisbury diffs, there is a hinged, cushioned plate that bolts directly to the diff "nose". I am assuming that because the Explorer diff is cushioned, this can be stiffly mounted otherwise to the cross-member. If so, I was planning to do exactly what you describe. Do you have a picture showing this detail on your build?

Sounds like a fun project. Post pics as you go along- BTW, how far along are you at the moment?

Bob

I have purchased plans and am disposing of the 1938 Dodge Sedan that is sitting in the space I will use for the build. I am in the process of collecting tools and materiel. I have yet to build my jig table.

I am recording the build on this thread: 289 Plans Build

There are two things that describe me best. I am a researcher and a sharer, so I plan on providing a detailed build thread, to include mistakes I make on the way. I think there is a greater good that makes recording a build of this nature.

Thanks!

Drew

[MAStuart]

Drew The best advise is come and see me. It should take you about 3 hours or less to get here . I am located 12 miles north of route 80 in Mendota Il 61342. Bring your diff along for a ride . You will be able to see if it would fit in an original style leaf spring chassis. I am building 2 of them. You will see the tools I am using. I am building in a home shop.But beware the place is a mess. Meanwhile Check out my build thread . You will see how close of a fit that an original style diff is. The thread to my build is located here scratch build

[120mm]

Originally Posted by MAStuart

Drew The best advise is come and see me. It should take you about 3 hours or less to get here . I am located 12 miles north of route 80 in Mendota Il 61342. Bring your diff along for a ride . You will be able to see if it would fit in an original style leaf spring chassis. I am building 2 of them. You will see the tools I am using. I am building in a home shop.But beware the place is a mess. Meanwhile Check out my build thread . You will see how close of a fit that an original style diff is. The thread to my build is located here scratch build

I will do that very thing.