unleaded valve seat coversion

[rick anderson]

I believe Harley davidson sold bronze replacement seats back in the day. I also seen them in v-twin catalog.Some one like olddude.com or n.o.s parts.com might have them or you could make them. You don't need as much interference with the bronze because they have the same or close to the same expansion rate.
Im not sure what interference I woud use but it would be less stress on the head for sure.Don't forget to swage the seats in, this will give a little more insurance on keeping them in place.

Rick.