I understand, well, I wish you the best of luck.

Again, I think the contribution of the hardness of the washer to the overall friction will be negligible compared to other factors like surface roughness (from forge scale after heating/quenching) and whether or not you apply grease/engine assembly lubricant under the head of the bolt and under the washer.

 I found head bolts with washers, but bought a whole cylinder head, complete with valves, camshaft and gasket set. The old headline did raise questions, hence my decision.

But the beginning of hardening with the burner on sand gives me the impression that there are many possibilities. When the engine is running again, I'll get to work on that.

Cheers, Willem.