My son has a 67 with a 79 302. Intermitently it has very low oil pressure on the stock gauge. It happens mostly when hot but only when driven, it could run forever in the driveway and have at least 1/2 a gauge. Once it drops it stays that way.

Pulled the oil pan and was going to replace the main and rod bearings hoping it would tighten it up a little. When I pulled the pan I found at least 1/2 of the valve stem seals (in small bits) in the pan.

My theroy is that when the car was driven and run over 3000 rpm the seals would be sucked up and block the pickup screen, the screen was deformed and some of the seals were weged in the baffle. Glad they did not pass thru the bypass hole and lock up the pump.

I replaced the bearings, pump and pickup and it's cured. Also replaced all the valve stem seals (what was left of them). I found 7 of 16 still intact and what I found in the pan and heads almost makes up the 9 missing ones. Going to pull the pan again in a few weeks and see if any other bits make their way down there.

 

Glad you solved the problem, good think nothing more serious happened.

 

my mustang reads a bit less than halfway on my oil pressure gauge. I always figured it was just faulty gauge since car didn't have any overheating issues but reading this makes me wonder. I might need to do the same thing to mine. How long did it take you to do the work on yours?

 

I do not think I would worry unless the oil pressure drops way off when hot. I would also verify the pressure with another gauge as the stock gauge is rarely accurate. The entire job took about 8 hours.

You could pull the valve covers and look thru the springs and see if the seals are still in place, you may also find some on top of the head if yours are bad.