built a 454 to 420 specs. High volume pump new mech gauge, cold oil psi 75 lbs. Hot it goes down to 42lbs around 4000 rpm and up slow down and cruise 3-3800 46 lbs. The motor has only 25 hours on it. I have changed oil 3 times and run WIX filter and K&N no different and I have run 30wt, 40wt, and 20w-50 all same. My clearance on the crank are as follows 1-.0026; 2-.0023; 3-.0022; 4-.0023; 5-.0029. Every other motor i have built always carried a steady 60lb.

k,
Did you measure the distance from the oil screen to the bottom of the pan ? The fact that the pressure comes up when you slow the rpms down to 3800 tell me that the pump might not be getting a good supply of oil. If the pickup is too close to the bottom of the pan, the oil cannot get into the screen fast enough. If its to far from the pan, it could be running out of oil if the oil is not getting back to the pan quickly enough or if the pan is not designed correctly.

If you put a couple of extra qts of oil in, it might help lead to the problem. If the pressure is better, then I bet it is a problem getting oil to the pump. By the way, are you sure the dip stick is correct ????

Bill Koustenis
Advanced Automotive Machine
Waldorf Md

It is set at the same height as stock and the oil pan and dip-stick are stock. The psi drops slowly as it warms up. If I run it hard it goes down to 42 but no lower if I slow down to a 3-3800 cruise it will slowly rise back up to 46psi I keep thinking my oil cooler is not big enough since it is a stock 330hp one. I am going to install a oil temp gauge to see what my temp is. If ok I will pull the motor over winter check the mains and install a new oil pump

You might want to look at more oil cooler capacity. Sounds like the oil is getting a little to warm. On clearances always remember to not get to big with rod side clearances also. When these get on the big side they will drop oil pressure considerably and make it harder for the oil rings to control oil consumption. Just some thoughts.

Ray @ Raylar

I know my rod clearances also; 2.1989-2.1992
.0025-.0022
I don't know if that is good or bad the machine shop did the work and I put it together. I just think I should have more oil psi than what I have. When my gauge gets here should I put the sending unit on the pan or right above the oil filter location on the block?