Lifter and valve noises..? Low profile covers an issue?

[briscuba]

Hi all,
I recently bought a 1970 original 402 bb in my CST/10. I have done a full tune up, and valve adjustment. Valve train seems to be fine. I am still hearing a light "ticking" noise coming from my motor - as I did when I bought it. Knowing it was an older motor, I put high millage oil as well as Lucas additive. I thought that would quite it down, but no luck. I have ruled out exhaust leak for the most part (Headman headers, common issue, I know...) as it really seems to be a metallic sound.

I have heard that on some of the late 60s big blocks, that the low-profile (mine) valve covers sometimes were a problem. Can anyone confirm this? Do the rockers sometimes hit the cover, and make noise? I attached a pic of truck and motor.

Thanks for your input!

Chevy Brian