Fuel Pressure Problem

Laredo GN

Anyone aut tehre
I have a 1985 GN and I have to run the fuel pressure way up high 60 line on because If I put it on 45 line off, when the car is at WOT it does not go past 45, it stays the same. If I have it at 60 at WOT it goes according to the boost 60+15 =75 PSI. Could the pressure regulator be malfunctioning. the car also detonates at WOT. The car runs real strong what do you think the car should run with the following modifications: Can P put on a Holley Red pump to help the Non-Wired in tank fuel pump supply more gas.

2800 Converter
3" UP & Down Pipe
390 gears
Home Ported heads
Poston High Volume in tank NOT HOT WIRED fuel pump
Recenty Overhauled with Postons High Performance overhaul kit
3" Exhaust from Down pipe to the rear tires with Flowmasters
86 ECM
Postons 93 Chip
160 Termostat
Throttle Enhancer Calibrator
Fuel Prsssure Regulator
Blue Top Inj
Cool Ait Induction
12 inch K&N
Boost & Vacum Gage
Trans Cooler
2 1/2 Cross over pipe

1040 GTX 440 Six Pack
1959 Roadrunner 510 CU 10:80's 1/4
1993 Z28 LT1 with several Bolt ons