DIFFERENT kind of oil pressure question
 

I have searched the internet several times over, and I always find different answers to the same old question...what should your oil pressure be on a FLATHEAD V8? Now...what I want to do is start this thread to see what people actually have. Can you post your type of V8, Mileage, Type of oil, and hot/cold PSI idling and running, and what type of gauge you are using? (Also if you are running a high volume pump, please specify) For Example:

I am running a fresh 239 Flathead 8BA.
Engine has less than 100 Miles.
I run 15W 40 Delo Oil.
Cold Idle- 50#
Hot Idle- 25#
Cold Running- 65#
Hot Running- 55#
MECHANICAL GAUGE!

Every post about oil pressure has what people think you should use for oil, and what they have. They always say "My flatty has 40#" but they dont say hot or cold and what type of oil they are using. The more information the better!!

Mine is very similar to yours, running 10w30. But this will be meaningless unless the gauge used is indicated. My dash gauge says it barely gets to 35, but a real gauge shows just what you are seeing.

Great point! I just edited the original post to see what people are using.

I put a lot of faith in bobistheoilguy and I am of the understanding that 10#/1000 rpm hot is acceptable. I also am a big believer that too much oil pressure can be a bad thing from parasitic hp loss to washing out the oil at the bearings.

Just built a 239 flathead and am expecting 20-30# hot at startup on 30 wt oil. Engine is tight, the tight end of tolerance. I will repost here when I finally fire it up.

BTW, I also have a 8MC in an old Customline. An obvious transplant and it is in dire need of a rebuild. Still starts up fine and with straight 30W hot it will idle with 25#. It's running a cheap mechanical gauge from Autozone. If it didn't smoke, I wouldn't bother opening it up. Probably going to just pour Marvel in it for a few frequent oil changes and see if the rings unstick...

10 lbs per 1000 rpm is also what I have been taught.

15 lbs minimum at idle.

1947 car 239 flathead either original or very old rebuild.
20/50w
mechanical S/W gauge:
cold @ idle is 80psi
warm @ idle is 20psi
cold @ running is 100psi
warm @ running is 50psi
Stock gauge on dash:
cold pegged @ idle
warm @ idle is 18psi
cold running is pegged
warm @ running is 47psi