66 dart rear end swap

Ill take a stab at this.

The easiest is to find a donor car same year and model with an 8 3/4 rear, driveshaft, shock plates, u joints etc.

The 73 f250 rear you have have could be shortened and reworked to fit but it would be the same work as an 8.8 ( i'm assuming it is a ford 9") but if it is a full floating Dana 60 or the like there would be more work involved.


Depending on what you are planning to do with the car and HP out of the engine you could just stick with the 7 1/4. There are many members who have put HP into a 7 1/4 with out issue.

There are lots of vendors (Cass at Dr. Diff) who will sell you a fully rebuilt rear the correct size and be a bolt in.

ultimately if you want to do an 8 3/4 swap you will need the following:


8 3/4 center section (like the 3dr member on a ford 9") with the correct size input yoke for the u-joints
A-Body 8 3/4 axle housing
A-body 8 3/4 axles (small bolt pattern to match your front wheels)
You can reuse your 7 1/4 brakes ( most likely)
brake line for the housing
brake line terminal block
Axle vent bolt
flexible brake hose from axle housing to body ( diferent depending on the year of the housing)
8 3/4 U bolts
8 3/4 Spring perches
U joints
Drive shaft


Looks like you want to change the transmission too

transmission
proper sized output yoke for the u joints
mounts
kick down linkage (not 100% sure of that)
flex plate ( not 100% sure of that)

NONE of this is cheap.
you can see where a donor car might be cheaper.


Good luck to you.