Viton or stock umbrella seals

[62 Comet]

Which would be the better choice for keeping oil out of the cylinder? The Viton seals from CI or the stock umbrella style. Its gonna be 20 bucks here for me to get umbrella style ones. CI has got Viton for 10 bucks and then shipping, maybe 10-20 bucks.

Anyone know the pros/cons of either of these, b/c I'm in need of replacing them

 

[MPGmustang]

the viton seals IIRC are teh better way to go, they have metal bands so tehy stay on the valve guide stud better. the umbrella seals work but I ahve seen them flow to the top of the valve stem and break/crack when valve is opened again, but that's after 100k miles worth of reliability.... both will outlast the head if taken care of properly. I like the viton due to the face it won't 'float' with the valve stem.

another thing to think about is if your valve stem studs/guides need to be machined. I don't know so make sure you ask whats required to run the viton. I know mine is machined, but I have valve guides.