My car is running really rich after a fuel system upgrade

Heres my setup
393 stroker big roller cam
Quickfuel Q750 carb

I added a sumped tank and -8 lines witsh return setup

Before fuel system change i was running 70 & 80 jets

After change it was running really rich fouling the plugs

Changed to 67 & 77 jets still runs rich

is it normal that i would need to jet that much lower?

Out of box settings are 74 & 84