408 Valve train noise??

Something I didn’t mention as I felt it was insignificant but perhaps it wasn’t?? When it was first suggested that one or more of the rocker arm bolts could be loose. I grabbed a ratchet and starting checking every one of them.
I did put about 1/8-1/4 turn on the #4 exhaust rocker. My torque wrench is old and well used and a lot of improper use to add.

I went out and purchased a new one and proceeded to check them for the proper torque value and all were at least at the desired 25ft lbs possibly more as I didn’t loosen any.

Someone suggested a bottle of Lucas oil stabilizer. I bought a quart of it today and drained and added it to the fresh oil in the engine. It also raised the hot idle oil pressure additional 10psi from 25 to 35 this is with 15w40 Rotella T4 .

Went for a road test and to be honest the noise seems less noticeable. Still there but if not my imagination about 1/2 as pronounced as it was before.

Other than almost a fire from a spraying O ring on the fuel filter housing of a Summit Holley dual inlet line with gauge that covered the manifold and right valve cover in fuel it was an enjoyable drive.