Exhaust Valve Question...

dgc333 said

The umbrella style seal just sits on the valve stem, it's going to move up and down with the valve to some degree.

You can have the valve guide machined to accept a positive seal like whats used on a magnum head where the seal is positively attached to the guide and the valve stem slids through it.

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yup. There are also later style factory rubber seals that do fit sung to the guides, but are not teflon, and arent very thin. I use them a lot to replace the umbrellas, because they dont move with the valve. the exh ones are much shorter and are sometimes a different type of rubber, because there is no vaccum trying to draw oil into the guide and the port, and the valves run hotter.