Champion Irons - Viton or teflon valve stem seals?

[TR Custom Parts]

Had teflon on mine and after about 15 thousand miles I have some slight smoking on occasion. Exhaust valve guides have wear, would viton be a better choice?

 

[Kip]

Use Viton and don't look back. Of course they will not fix what has already happened.

 

[TR Custom Parts]

Guided being replaced. Will try vitons this time around.