408 oil pressure issues

So it still drops back down when hot. Quite possibly one of the most notable observations is that when a filter is fresh, I can easily get 60+ psi. After a few minutes, I will drop pressure and 40-45psi is about the max I'll have from then on. This is an F body with 2.45 gears so 5000rpm even is rare. I do have hollow oil-thru pushrods. Oil never has any signs of coolant.