[Mike S]

I just fired up the fresh 400 a couple weeks ago. I used a summit 2801 cam and lifters. Cam break in went great. Have about 100 miles so far. Engine runs great, sounds like a stock cam. Oil pressure is 38 hot at 600rpm. Running 10-30 oil.
I noticed on start up after it sits for a few hours I get valve taps until the oil pressure comes up, maybe a few seconds. It sounds like the lifters bleed down after sitting a while. I never noticed this with the old 455, but did have louder mufflers.
What would cause this? Is there a one way valve in the oil filter that can be leaking? It is a wix filter 51258.