What E-series diff's interchange? I'm mainly talking about mounting points, but other details may be helpful to know. For example can I bolt an EB diff into an EL? Or visa versa? V8 into I6 etc.

I just want to know if any E-series diff will fit any other model in the E-series. Or if there were changes made along the model lines that stopped any interchanges working.

I have fitted both an el and Ef Diff into an ed and used the original brakes and lines you can do the brake conversion if you are keen on doing the lines as far as I know eb1 has different sized lower control arms mounts and as for 6 or 8 they both are the same. Supposedly you can also put au live axle setup with some minor mod but I can't find too much on this. Hope I helped ya a bit

EL diffs had a different upper mounting point for the upper trailing arms, and the rear cover had the Watts link pivot at a different point....20mm lower???????....and the park brake cable arrangement is different too....i think???????
The XR6/8's had different upper trailing arms too.....and mounted in a different hole in the bracket on the diff.
EA to ED used the same rear calipers ( park brake included ), and EF, EL, AU1 use the same idea for caliper and park brake inside the disc rotor, like a drum.
AU onwards are a wider track than all Falcons previous to this.....hence the wheel offset changes.

Nice summary cjh.

The reson I'm asking is I bought an EF XR8 that has a brand new 9" fitted. The body was being converted into a race car so it is too far gone for the street. But I wanted to keep the 9" and fit it to another body.

From what you are saying, I need to be searching for EF/EL XR6/8 bodies only.