I have had this problem on 2 of my chevy motors.
Both with diffrent solutions the first was a wore out spring causing the valve to float at any rpm above idle

The other was on a big block and yes it had worn cam lobe the ticking was from the push rod droping to far and ticking when i hit the rocker at higher rpms and causing a top side back fire

First i would check that side valve springs and hope that is what it is

good luck with the problem