I have a 383 it was built 15 years ago driven 10 miles and stored,I put it in my 72 camaro started it it gets good oil pressure until it warms up then drops to 15 lbs at idle 40 when at 3000 rpm ,I tryed different oils same problem.anybody seen this before? what do I do next? I want to drive this 500 hp car on the streets.   

That sounds perfectly normal, your worrying too much. go out and enjoy your hotrod.  

I agree.

Many engine builders have said that ALL the oil pressure a small block Chevrolet needs is 10lbs per 1000 rpm.

Relax.    Enjoy it.

I have been told that,but they said I should have 40 lbs at idel,what concerns me thar it does when its started but when warm it drops now even below 15 lbs I shut it down when it gets noisy.  

Could you bump up your idle? What rpm do you have it set? How much does your oil pressure come up when you give it a "little" throttle? 

Once it's warmed up fully, how much oil pressure do you have when you raise the rpm's?

What oil do you use? Straight 30, 40, 10w30...?  You may be able to switch to a heavier oil like 20w50 to indefinitely postpone a rebuild.

Just some thoughts.

Another thing you might want to think about is what the bearings or rod clearances are. If the motor was built for any kind of high performance/racing applications you'll have less oil pressure at idle. I have a 454ci that has been set up with more than stock clearances in the bearings, rods and crank area. My oil pressure is 15lbs hot (180+) at idle in gear and 50lbs at 3000 rpm. When cold it has 40 to 50lbs idle and 80+lbs at rev. This is with a high volumn, high pressure pump, "O" rings on distributor, hyd lifters using 30wt oil and oil filter bypass plugged off. This eng is in a daily driver with no problems what so ever. 15lbs at idle for a chevy eng is ok. Like Yellochevello said, bump the idle up a little and try it.

it sounds like the same thing,this is the first i head of it and i asked every one,it still bothers me when i hear it get noisy,its the same with 10 30 10 40 20 50 sound like i have too much motor plus there is no place to get race fuel,any one want to trade motors?  

hello,

First question I have is, is it a solid lifter cam, if yes, check valve lash, though it should have been a little noisy even at start up. Next, is the oil pump an old used one, if so too much clearance is probably the problem, you could put a Z28 oil pump spring in it. Check valve lash  on it if it is hydraulic. If any or all of this has been done then I'd check bearing clearances, sometimes when an engine has been sitting for a long time, the oil breaks down and you end up with acids in the oil that eat at the bearings thus causing excessive clearance.

thats what happened,its being rebuilt now.thanks  

i read that you have your oil bypass plugged.  how does this help?  some people tell me not to plug it, but doesnt it let unfiltered oil through the engine?  i cant imagine that there would be any benefit from pumping unfiltered oil through the engine.  thanks for any help you can provide.  

that question was for tom91653.  thanks.  

I'm down for a swap...and I'd love to stroke out my truck, lol !!!
But, I'm sure you don't want my 4.3, lol.....  

Hey Chevnut, please post how the bearing replacement did for the oil pressure. I have a 91 Z28 and just replaced the oil pump, main, and rod bearings. When I first started it up, it had about 45psi. After warming it up, it gives about 20-25 psi at interstate speed. But when it idles (about 600rpm), the oil pressure gauge is almost zero (assume about 5). I replaced the stock bearings with 1000 thunder bearings. Anyone have any ideas?

If the cam clearances are off, would that cause low oil pressure?