That is good to know, another piece of the puzzle. I had been looking for a set for some time now. didn't think I would find them in a swap meet. Don't have the budget for aluminum heads but didn't want to settle for stock either.
Since they are bare castings you will need a machine shop to size the guides and touch up the valve job once you get valves.
IMM engines in California may still offer valves and a spring package for these. You could check with them.
If not, Hughes Engines can get you a spring package and valves.