First off I would unscrew the sending unit with the 2 wires on it and get a manual pressure gauge, Where you hook the oil line in, where you unscrewed the sending unit that way you will get a true reading of what the oil pressure is 30-40 psi is good when cold and when warmed up 10-20 is not bad how many miles on this Good Old 360,any knocking when you put it in gear and do a brake stand or brake torque, is it holding good pressure, your mains and rods get oil first then your cam and upper valve train, do you have allot of valve ticking
or minimal, your mains and rod bearings may be worn thats why you need a manual gauge.