My home inspection of Speedmaster heads

rednesss said
So, if you wanted to have a better valve job done on these heads, would the machine shop have to put in all new valve seats, or could you cut a 3 or 5 angle valve job using the existing seats and then also re-use the existing valves?

A shop with a Serdi (or other brand of seat cutter) could do the same with radiuses. Those machines cut the seats using carbide inserts instead of grindstones.