[Rust-O-Matic]

When you pushed with the hammer handle did you push on the lifter side of the rocker & how hard did you push? It could be a bad lifter, I sometimes need to put a lot of force on it to make it show.

What is your oil pressure? With low oil pressure the top end starves first.

I mainly pushed around on the valve end of the rockers with the hammer handle, because I had read a bunch of stuff about 305 valve guides/seals wearing and making noise due to the slop it causes. Would a bad lifter cause the noise only when warm, or would it do it all the time? I could pull that cover back off and push on the other end of the rocker if I knew what exactly I'm looking for. Oil pressure is up between 40-60 psi when driving lately, but was a little lower than that before the 10w40 and Lucas. At idle the (when pressure is least) the tick is almost inaudible. It's worst when maintaining speed going down the road, or decelerating.

Double check for exhaust leak. They can sound real close to an engine tick.

Do the plugs for that cylinder and the adjacent one look normal?

Warm the motor and pull the belts. See if the noise goes away. Had a PS pump that started making a knocking noise right after I had installed a new crate motor. Was really happy when the knocking noise stopped with no belts installed.

Exhaust is all brand new from headers to tail pipes, but I'll double check the header and flange bolts anyway. I didn't think to check the plugs in that area; that's a good idea. The only accessories I have are alternator, water pump, and power steering pump, all three of which are brand new (though, these days that doesn't mean much). I checked them with the stethoscope while I was at it and did not hear the noise. The noise is most prominent when I touch the stethoscope to the front 1/4 of the passenger side valve cover.