I have a 540 big block with solid roller cam and The oil pressure is not as good as I would expect it to be. cold it's like 55when it's hot running it's like 40 and drops down to 15 idling hot have a new millodon high volume oil pump ,bearing clearances are all good somebody was talking about putting oil restrictors in the back of the block and that it might be bleeding off in the roller lifters. Oil temperature is between 190-230 . I'm at wits end with this I pulled the motor apart because the pick up tube cracked but before that I had about the same pressure. Oil pump clearance was a little loose but the mains and rods were perfect I put a new oil pump in it and a bigger capacity oil pan read did all the oil lines to the filter and it still doesn't have the pressure I think it should have ! I would expect to have 80 cold and at least 60 cruising hot and 30-40 at idle hot . I would appreciate any input on this thanks
Ritchie

What was done to the block at the filter?
Are you using a remote filter and if so which one?
What size are your lines?

Have you read through this thread?

http://www.offshoreonly.com/forums/g...-hardware.html

Smitty did a good job with that thread. What gen is the engine? I remember years ago I had one engine noticeable down from the other but never showed any signs. I ran excessive bearing clearance then due to cold water temps and no oil stats so I just put it off on that. It didn't fit the rule of thumb of 10 pds per 1k rpm. Hot I was at 40 psi wot extended run periods.

Do you have the screw in plugs in the oil galleys behind the timing chain in gear or are they the drive in type that look like freeze plugs? I haven't had the pleasure of dealing with all the newer generations so I'm not sure if they are still screw in or not. Just trying to think outside the norm a bit.

Or regulator stuck open on the pump...wouldn't be a first time.

True.
Also OP is this a new build for you or a rebuild. Any changes in oil plumbing, bypass. Just trying to think of any changes you may or may have not done.

You may have a cross-drilled crankshaft, they use quite a bit more oil.

Verified with a mech gauge? Mine was reading about 20-30psi low until I checked it and bought a new sender.

what is the lifter to bore clearance?

what oil pump did u use, and did you install the higher pressure spring.. A stock melling pump comes with a 40# spring