It's happening to me as I type this. Head needed work, unemployed. Took it to my engine guy and told him to budget freshen it up. He said you need hard seats. I know, but not in the budget, can you buy me 10k-15k miles and then we'll do it right?
Guess what? I'm about 8-9k into those soft seats and it's acting like I need to loosen the valves up some.
The first valve grind on an induction hardened seat will probably go thru the induction hardening. It's only .005" to .030" deep. I don't see any point in scrounging for a late model set of heads if that's the only reason for them.