Relocating the rear differential 1.25” towards the rear of the vehicle on a 72 Dart

Going to call Calvert Racing in the morning and check into a mono-leaf setup with caltracs.

Not too sure about how it will behave on the street.
I have a 72 dart setup identical to what you are talking about, dana 60 moved back 1.25, caltrac setup with sliders etc. I drive it a ton on the street and a fair amount on the freeway and I can say I think it drives better than it did with all the stock stuff. Is your car painted green go?, that's what color mine is.