390 oil pressure problems

New to the .org and "search" wasn't working. Looking for some insight into a problem that I'm having with my Galaxie fastback.

Car has been in storage for a few years, run occasionally to keep things lubed. I pulled it out of storage and started driving it on nice days on the weekends. Maybe the car has 50 hours of runtime on the engine total right now. It has an ISKY cam in it with a little overlap and an aluminum intake mainifold so low end response is a little poor.... it really lopes at a stop light. Bored 30 over with a 4 barrel Carter AFB. Compression seems fine, plugs burning clean. Haven't had a chance to put dual exhaust on it yet. It runs a little hot...but then again I'm in Texas.

Noticed the following: 1) a little leakage out of the main rear bearing seal. Installed a new PVC and breather and it appears the problem stopped.. 2) At a stop light, noticed the oil light flickering (in Park, oil pressure light is off). Using 10w - 40w. Went and puchased some gauges and was surprised to notice oil pressure at about 10psi at idle and 20psi at 40+ MPH. However, at a stoplignt oil pressure drops to 0. Top of the engine seems to be getting enough oil, there's no lifter or rocker noise at all.

I have no idea about the main bearing clearences (whether they were on the high or low side) when it was rebuilt. I don't believe (but really don't know if) the oil pump was replaced when the engine was rebuilt (car had 163K miles on it before I restored it).

Any insight /thoughts/course of action would be welcome (ie. what would you do?)

If it was mine and I was sure of the mechanical oil pressure reading, I would drop the pan and inspect/replace the pump and pickup (Mellings). I would also plastigauge a main and rod bearing while there.

It does sound odd though as low oil pressure will usually cause the lifters to tap lightly first.

Vinnie,
Where did you tie into the engine to get your oil line to the gauge? Maybe you should try another spot like on the oil filter bracket or somewhere close to there. I'd try somewhere else and with a different gauge before I condemn the oil pump if I didn't have any lifters rattling and was getting plenty of oil up top.

Did you have good oil psi before? With just a light to determine engine condition I would doubt it. With such low mileage on the engine your probably ok. But get out the tools and pull your timing cover and timing chain and install the oil galley plugs that your engine builder left out. I believe the driver side plug is recessed behind the distributor and is very easy to leave out. The fe engine has a very good oiling system so i bet you did not do any damage to the bearings.
What year is your car? just being nosy...