oil pressure in 440

[hankrivers]

i have a 440/727. when i give it gas the oil pressure drops as the RPM rises.when i let off the gas it goes back to normal( 15-20 psi at idle, 40 psi at 2500RPM cruising). i put in a MP oil pressure spring kit and it had pressure when i started it, i went to the gas station (2 miles) got gas , restarted the car, and ZERO pressure?! i then installed a MP high volume oil pump, primed it and still zero pressure.
the motor has a milodon pan and pick-up, windage tray and new oil filter.
any ideas? where should i look for the problem?
any help would be greatly appreciated. thank you very much.
Henry.:confused:

[PRO]

1st,do you have an electrical gauge or mechanical?if electrical then the sender or gauge could be at fault especially if you dont hear any knocking or clicking,so verify with a mechanical gauge,is it running bad? like on 7 cyls?you may have bent a pushrod which allowed a lifter to jump out of its hole and thereby dropping any pressure reading at the gauge,just pull the valve cover and check,this once happened to me and I found a broken rocker shaft too,if all looks good there then pull the pan immediately before you do any damage and plastigauge the bottom end and dbl check the pickup tube and its clearance.Hope this helps......PRO........

[hankrivers]

i have a mech. gauge. there is no oil flowing through the tube that goes to the gauge.
the pick-up to pan clearance is right where it should be.
i checked the drive gear on the distributor, it's good.
the top end is all good. i can start the motor and it will run fine...except for this little oil problem....aaaaarrrggghhh! i heard the lifters getting louder after the pressure went to zero. so i haven't run it since.
if nobody can suggest a simple cause for this i'm gonna just rebuild the bottom end(it has about 15,000 miles on it).
thanks again.
henry.

[Glen440]

I would pull the valvecovers and intake off first for inspection.
My brother thought he blew up his engine when he bent a pushrod and it did what Pro said- lifter came out and oil pressure dropped. We ended up pulling the engine and found the real prob, so we did that for nothing. We also had a no oil pressure prob on a 440 once. Don't know what it was but we primed it and it got pressure and was fine after that. Figure something got stuck in the oil pump or ?.