What is considered "normal" for a 305 stock engine (with original oil pump etc?)

jd

With Mobile 1 oil 10W30 at idle and a hot engine from 20 to 25 is good if your using regular oil (Non-synth) idle hot would probably be around 12 - 15 something like that. You only need about 12 to 14 for it to operate properly and could go as low as 6-10 psi without damaging anything.

On the highway you should get between 25 to 45 psi depending on the oil. The synth oils will have better viscosity and hold up in heat better and will show a better pressure both at idle (hot) and on the highway.

@ 6 to 12 psi you have enough of a film surface to keep the bearings from chattering or touching the crank. So 12 psi is not that bad, it just looks bad. Aging oil pumps and Dino-Oil will be low on the gage but that doesn't mean that things are bad, just worn some.

Thanks ElkyPete

Thought maybe this motor was lower than normal. Runs around 30 with dips at idle.

Thanks again

That sounds about right.

I run 20-30 at idle & 45-55 at cruise.

my elco runs 60 at idle and nearly 85 when crusing

My 78 350 o/p runs about 35 psi when cool and drops to around 5-10 psi when warm and at an idle. Is this acceptable? I was thinking it was from bad cam bearings.

You need about 10 psi for every 1000rpm upto about 40 psi. Any more oil pressure is detremental to performance and unecessary. Much less than 10 psi at idle probably means a worn engine.

Could low oil pressure be caused from a bad oil pump? What are other causes of low oil pressure?
:?

What are other causes of low oil pressure?
:?
the fact that the engine is 20+ years old in my case

Could low oil pressure be caused from a bad oil pump? :?

Defenitly

Low oil pressure is usually caused by wear, in the oil pump and all thru the engine. Replacing the oil pump will usually give you more oil pressure and additional life on the engine. However eventually the engine will have to be rebuilt and the proper clearances restored.