I got the gasket set for 2 of these I have for $18 on ebay from the good ole country of the stripes and stars, they are not perfect gaskets but they are much better than I would have the patience to make with gasket paper and scissors.
Generally unless the valves are pitted badly I just lap them, then reset the clearance.
Rings should be easy to get, I am pretty lucky with mine both had good ring gap and replacement wasnt neccecery.
