396 experts need help

[69 customcamper]

Hey Guys,

I rebuilt my 396 which is a 69 block. Have the Camaro Heads with a Melling MT6 RV Cam. I ended up Putting Poly locks as the replacement Rocker nuts kept coming loose. Factory ones stayed tight. It has 20-50 oil with Zinc additive and 50 PSI oil pressure at idle with a mechanics oil gauge hooked up. Sounds great when cold. Once it hits 185 - 190 degrees , it idles a little rough and sounds like lifters clacking. Done valve adjustment 10 times. I used 3/4 turn. Tried 3 different oils........ If I missed one of the oil plugs for lifter galley on front of motor behind the timing gear , Would I still have 50 psi ? (Doubt it !) . Plugs are staying white so I am thinking it is also lean. Compression is 150 psi all 8 cylinders.......... What else ? Almost ready to yank it and build another motor. I pulled the Bypass valve this morning and it seems good. No gasket although I do not think that would change much other than possibly mixing a tiny bit of unfiltered oil with filtered oil ?