14-09-2022, 09:00 PM
You do come across old Ex grade valves in some A7 blocks, I have found them to be good quality so regrind and reuse them if the stems are not excessively worn. I imagine that all valves now sold by our cherished suppliers are of similar or better quality, I have certainly never found issue with new valves from any source in the A7 world. If I were to be critical at all it would be that the seat face can be a bit wide on some new valves which reduces the effective opening area. If you have a lathe a small performance advantage can be gained by removing that excess material. Looking at the OP's block, I think I would be inclined to replace them all with new.
Black Art Enthusiast