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

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.

Did the 1.25” relocation affect your shocks and differential potentially hitting the fuel tank?