340 X Head Value
i sold a set somewhat recently that needed a full rebuild and had a stripped rocker hold down for $200 and the guy couldn't give me the money fast enough.
i'd say that yours are worth easily double that, but they show signs of flash rust and have some used parts in them so they'll need to come apart for cleaning and inspection-- and probably replace the seals.
on the positive side, they've got new guides, new seats and are set up to take .550 lift.
i don't know what you've got into them and i don't know what a machinist would charge to roll thru them and clean/inspect/replace things and stuffs but the tipping point of non-ported steel heads seems to be in the $800 range. i'd throw $600 out there and see what kicks.