Regulated fuel pressure on a QJ at 5-5.5psi will supply enough fuel IF the n&s is sized correctly......pardon the digression...
Most if not all stock and super stock cars have the fuel supply sump (tank or cell) in the rear, so the system pressure must oppose g.....
Adequate Fuel Supply? The following chart is for gasoline.
In case you have forgotten, without data, you are just another guy with an opinion.
Regards to all that like this kind of stuff, 
HB2
Dissident