Fuel pressure dropping while driving and under acceleration to zero at idle runs 4 lb electric Blue

If I were you, I’d look in to a Holley pump that replaces the original sending unit and puts the pump in the tank. Seems the easiest solution to me. And if you use a carbureted regulator you can drop the pressure enough for a carb.
Holley Sniper EFI 12-319 Holley EFI Fuel Tank Modules - 255 LPH - Mopar A-Body
Do you know if they make a pump like that that will handle more horsepower than 500