If you are going to use the GSL-392 for the NOS. I would use the Mallory 4307-M, they have changed the part number though to the one below. It is rock steady on Fuel Pressure and does not creep like the little chrome holley regulators. You will also have a return. I plumbed a return into my "Big End" black pump using the Holley style regulator and a -3 hose with a small Nitrous jet. It works pretty good.