Carl,
Been there - done that (chewed up feeler gauges - on all my not-so-old 216/235/261 engines).
Chews up feeler-gauges and gives bad "readings".
The first step in
my valve lash adjustment procedure on a "new" (to me) engine"
"1. Make sure that each rocker arm surface that mates with the top of the valve stem is smooth. Grind smooth and polish, if necessary."
