I built a Pontiac 400. It has around 60 lbs of oil pressure at idle until it warms up. The pressure drops to around 25 lbs when at idle when warm. The engine has good oil pressure at about 2000 rpm, around 80 lbs. Never runs over 180 degrees. Idles at 750 RPM, Melling high pressure pump, Castrol Syntec Blend 10W-40, and yes, I did put the gasket between the pump and the block. Is this normal? What could be the cause?

I built a Pontiac 400. It has around 60 lbs of oil pressure at idle until it warms up. The pressure drops to around 25 lbs when at idle when warm. The engine has good oil pressure at about 2000 rpm, around 80 lbs. Never runs over 180 degrees. Idles at 750 RPM, Melling high pressure pump, Castrol Syntec Blend 10W-40, and yes, I did put the gasket between the pump and the block. Is this normal? What could be the cause?

As far as I can tell it is normal for the conditions you describe! I have built several 400's and experienced the same results! I have one in my GTO now that is running almost the same exact way!

Sounds normal to me john. As long as it comes up with the rpm as you noted it's fine. If you want more a idle run thicker oil.

Jon,

10 lbs of pressure per 1000 rpm is fine.
Therefore 25 psi / 750 rpm = 33.3 psi per 1000 rpm.

Matt in Milwaukee

Thanks, guys! That makes me feel a lot more secure about my engine.