66' 273 Knocking/Ticking

Did this "mechanic" pull the valve covers off? I've owned several 273s, I have never seen the rocker arms go bad even with high miles... Sounds like you just need a valve adjustment to me (which is typical after a rebuild has been run in...) Check 'em after you get your book, and like chryslerfat said they are easy to work on... good luck with it and welcome to FABO
X2.....I'd also add....when the valve lash is adjusted properly, you should still have a little valve train noise, otherwise, they're probably adjusted too tight. I like doing them HOT, and engine running. Kinda hard on feeler gauges but seems more accurate to me. You'll need to do it at a real slow idle or you'll have oil splashing around. I made a cut-off set of valve covers to keep the drain-back oil from dripping over the side of the head. I know, it's an aquired taste but I do the slant 6's the same way. Just be carefull holding the 3/8 wrench while turning the adjuster!