Thanks Brian, It all worked out in the end. I’m using Speedway Motors Unser edition rear suspension as well. Truck arm style with watts link. Narrowed 9” full floater rear. I was able to reuse my center section ( 3.70 gear with True-Trac 31 spline).
The rear end that was in the car was a 65' Chevy II 10 bolt 8.2" it had been upgraded to a 3.73 posi with 11" disc brakes. It has gone on to be reunited with a 65 car that was in need of a new rear.