Been a good read. I built this motor under the guidance of a master builder (hemi) but on a budget and as a practice motor. Unfortunately he is only available with occasional call because of illness. Hence some of the out loud thinking I am doing and asking on the forum. It was prior windowed block. But I had all the proper machine work done, test etc... Built to be a stock motor stroked to 4.15, but just under 10.25 to 1. While I have all the clearance data, the one exception is lifter bore. I know the lifters are stock size, just did not measure all the bores. Though I know that they are loose because of the honing required to clean them up. I am thinking more oil is the solution but will go step by step. I also think this post can be very helpful to the other building motors on their own.

So yesterday I swapped filter. Moved to a more traditional PH-8 size. Noticed the inlet ports where larger and more, then the one that came off. Cut the filter open and it had some of the assembly grease and such in it but no metal. Primed the motor again, then started it. Had a 10-15 psi increase in oil pressure cold. Was at 80 psi at about 2000rpm. As oil heated up and water temp about 140 and rising had good 45 plus at 2K, and in the 30psi at idle. 1100rpm. Once it warmed up completely pressure down in the 40 range and back down to 25 at idle. Running in the 2200 to 2500 oil pressure is ok, but once I go higher in rpm above 3000rpm and up toward 4K the pressure initially rises but then will start fluttering downward again. Not as low as before, but still down such that I am not at the 10psi per K rpm. I go back to idle for awhile. Then rev back up and it will climb right back up to the 50 even 60psi range, but flutter down again.
Probably could not make the 1/4mile without seeing this loss at the end of the run. Only does this hot and when RPM is above 3K.

Shutdown, drained water and oil after cooling. No oil in water and no water in oil. BUT I only got 3 quarts out of the pan. Plus one in large filter means I had 2 qts at least in the motor above the pan. I was able to work a dip stick under the stock pickup. I could rotate it about 45 degree, but not stand it up vertically. So it is close to pan, but with clearance. Also When I drained oil, I first just drained about 6 oz. No water just a couple of very small metal metallic pieces.

Pulled plugs and covers. Inspected and everything looked good. Rocker plugs in, only some signs of excess leakage around one short shaft at the angled stand (driverside). Otherwise caps dry and no signs the head is flooding with oil.

I think gauge is eliminated unless we think it flutters only when hot oil there. Otherwise it responds appropriately. Cam is Racer Brown H44 with Hyd lifter and stock rocker assembly. No pushrod oiling. No restrictor for head oiling, removed them as recommended.

Plan is to recheck lifter preload while covers off. Swap out the oil pump cover and refill. Then test. If still issue I will add extra qrt of oil. See how that works out.

I guess it is interesting. During an oil change with filter you would add 7 qts, but you probably only get 4 plus 1 for filter out. Meaning your really running with about 9 quarts on a stock motor after first oil change? 2 left in and 7 added?

Having watched several 440 and hemi motor builds and test with only 6 qts in, did not observe this oil pressure type of issue. But I guess my motor upper end could be using more oil that does not get back down to pan fast enough. Especially with windage tray. I did test fill the 70 pan, and if I remember correctly 6 qts was still under the pan baffle level wise.

Flutter is not really rapid, more like pulsing as pressure drops at higher rpm. Starts dropping off, might spike up, then back down, all while trending down at that higher rpm. So I hope this is the loss of suction head to the pump from a too low oil level.

On the bright side I rebuilt the original water pump and mechanical fuel pump and those are function great. More to follow, and thanks for all the insight.