^^^^^ that ^^^^^ and will add the unknown - after the rebuilds - New coolers ? the past cause for the engine rebuilds was ? so if old coolers were used how clean were they if any internal trash from the engine got in there ? Many will bring their oil coolers to a rad shop for cleaning but it is wise to go with BRAND NEW coolers. Just saying not knowing the unknown here.

I would mechanical gauge the readings as well to see how accurate they are .

If it’s done it since a rebuild check the drain back holes at front and back of cylinder head make sure there is nothing in the way...... head gasket or block deck

Did you install new oil pumps on the rebuild?

Makes sense.

ECU's were reprogrammed when motors were rebuilt.

Put a mechanical gauge on it and took it to the lake today. The mech gauge indicated about the same as the dash gauge at 3500 RPM. However, above that there was a difference of about 10psi (43psi at WOT). I also noticed my water pressure is too high.

Aerated oil is always hotter oil. When oil is aerated its thermal conductivity is reduced.
Temp increase is the affect not the cause.

GNJ - I feel your pain. I chased same issue for two seasons. Were there any bearing / crankshaft changes done during rebuild? I tried diff oil pump, diff pan, lowering oil in pan, replacing main / rod bearings, nothing fixed it. Finally got pissed and put new crank in and never had another pressure issue.

there’s a clear difference between the motors but not sure how you are sustaining 60psi on a factory 500efi if your oil pump hasn’t been upgraded.

Our 500’s start at 60 psi cold and once warmed up don’t run much more than 40-45 all the way up to 5200 rpm. After sustained high rpm running when we back down to idle they run at 20-25 psi. All of what I just said is pretty normal and well documented.

If anything engine 1 looks normal with the exception that it drops to 33 psi at 5000 rpm. Engine 2 looks out of the ordinary from what I have experienced for the past 4-5 yrs of running blue motors.

Thanks Scarab 28 & 1Moses1 for the good info. I have another larger oil cooler that I'm going to put on to see if that changes anything.

The factory cooler, block adapter, lines, etc are marginal at best...lots of info on here about that, I would change to a larger aftermarket cooler, block adapter(1/2 NPT) filter mount and and plumb with #10 lines, using a canton thermostat also would be a good idea..

Thanks EZ for that suggestion. I think it would be a good idea to upgrade all the oil cooling hardware as you mentioned.