i recently had my 396 rebuilt. i am having trouble with the oil pressure. when i start my the engine and let it idle, the oil pressure is at about 18psi. even stranger, when i rev the engie the oil press. drops to zero. i tried bleeding oil press. gauge, adding extra 3qts oil, using straight 50wt oil, but no luck. "please give me ideas or advice on situation".

You should have at least 10psi per thousand rpm's up to 50psi. Almost sounds like the pump pickup is either too close to the pan bottom or has an air leak at its juncture with the pump. I wouldn't push it, take it back out and pull the pan.

sound like something is getting sucked up against the pick-up screen.

Milan

If your using a Frmm filter change it to a Wix or AC Delco.Been having problems with the Orange filters recently.

so having 20 psi in normal driving conditions in a standard 350 with a 400 turbo trans is ok? or is it??

Man,
First of all, you should not run the engine any more until you find the problem. If the oil pressure is that low, you risk doing serious damage.
Next thing you need to do is call the person that rebuilt the engine and ask him what you should do. If you have a warranty, it will probably be voided if you continue to run the engine without finding the problem first.
The first thing I would do to try and determine the problem is to get a new, mechanical gauge and hook it up. Use a preoiler to spin the pump and see what type of pressure you have. You should easily be able to get 40 - 50 lbs on a new engine with 10w30 oil. If you cannot get that much pressure with the pre-oiler, then you need to pull the engine and find out what is wrong with it. If someone else built the engine for you, you should bring it to them to look at ... period.
Remember ... every second you run it with low oil pressure is that much closer to it coming apart !!!

There is a possiblity that there are pieces of slicone gasket material in the bottom of the pick up screen.

I second what BillK say's. Take it back to the builder. Don't risk voiding any warranty you might have while "trying to figure it out". Give the builder a chance to do the right thing before you do some serious damage.

Billy smile.gif