What is up with small block 350's...good oil pressure when cold and driving speed but almost zero when warm and at idle. I have a 350 in my 47 ford which I just traded for. The car has 23K miles with a 700R4 and 3.00 gears. When the motor is cold the oil pressure gauge (electric) shows betweeen 35 and 40 psi. Driving speeds it registers about 25 to 30 when warmed up. At idle when warm the oil pressure drops to 10 psi or lower. But as soon as I touch the throttle the oil pressure comes right up to say 25 or 30 psi. The motor is not tired and does not heat up. I had 3 previous street rods with  relatively stock 350's in them and they all had the same low oil pressue at idle when warm. And these were not old or tired motors either. I have asked other people about this and they say..oh that's normal all small blocks have low oil presure when warm at idle. What's important they say is if the oil pressue comes right back up when you hit the throttle it's fine. What say you out there?..any opinons?..Thanks, Ted  

It is not a problem.  Most chevy small blocks will have between 10 to 20 lbs of oil press when the rpm drops below 1000 rpm.  If the engine is stock, when it idles in gear when it is hot, the rpm is probably 600 rpm.  The performance engines usually run 60 to 70 psi when the rpm is over 1500 to 2000 rpm, but at an idle under 1000 rpm it will still only have 10 to 20 psi.  It won't hurt anything.  It will come up a little if you use 20/50 oil in warm weather.

Happy Motoring
Russ  

You must verify the accuracy of the gauge before you can confirm the the oil pressure is indeed as low as you think, if in doubt install a mechanical unit.
The mains hold the pressure in a SBC and low oil pressure may indicate time for replacement, when starting the engine after doing a oil change the engine will have zero oil pressure for a moment and the mains will let ya know real quick if the babbit is worn off.
If all is well in the bottom end then move on to the oil pump and check the pressure relief valve to ensure the plunger is not wedged open by foreign debri and the pickup screen is not clogged.
Last resort is to replace the pump with a high-pressure unit, high-volume pumps are tricky because they can suck the pan dry at high-rpm with a stock oil-pan...

Hope this helps ya.