Engine issue tap, tap, tap tap, tap, tap

[brown7373]

Developed a continuous tap on my stock untouched 72 350. Using a mechanics stethoscope, I am 98% sure it is coming from number 2. I tried the magic potion (Risilone) hoping it was just a gummed up lifter, but no help.

I am pretty sure I have a bad lifter. It starts and runs fine at light load, but hates even moderate acceleration and increased rpm. Any thoughts about anything else it might be?

My plan is to replace the lifters and pushrods and hopefully nothing else unless I find something when I get into it. Will driving it gently do any other damage until I get time to take it apart?