I am working on this swap/install in a 70 GTX.
I was hoping to at least have fitted the motor and trans by now but have been WAAAAYYYY delayed by major rust issues. Besides major progress on the rust repair, all I have managed to do is remove the motor and trans from the wrecked 07 Charger I bought.
There will be an AlterKtion front suspension for mounting the motor to and there WILL be some hump modification but have not been able to even go there yet.
My plan is to retain the 8 3/4 rear but install gear as close to the same ratio as I can get to the stock set up to get started with. Once the swap is done (I'm taking the computers and everything from the donor)and we get the car running good, we will start playing with different set ups (if I even feel it is worth it....this will be a driver not a racer of any kind).