I am running a 68 RS w/350 hyd.roller motor from a 90 Z28.I have a holley blue elec.pump mounted in the trunk w/mallory fuel filter and mallory 3 port regulator mounted by the carb.The liquid filled guage that is located on the fuel feed line on the carb will fluctuate alot from cold start to warm engine idling.When is this thing telling the truth?I am in the future going to put a 125 shot NOS plate under the carb.for when I need it.This is the reason for the 3 port reg.Is it nessesary to use a additional regulator for the NOS solenoid,and what is the correct pressure to it?And should I have to have a return line back to tank to save my pump?Your input on this matter will be greatly appreciated.