[rexus31]

My machine shop used teflon valve seals on my new heads. What's the popular opinion on these?

[big head]

ive heard that there good for the track,not so good on street,they let more oil past guides to aid i high horsepower application.you may get some smoke out the exhaust under hard acceleration..good luck

[blkcrow]

No expert here but Ive heard all the buzz about them being generous with letting oil pass but Ive also had them in two engines to date with excellent results.Two different engine builders and two different pontiac engines both street driven and raced and no abnormal oil consumtion or smoke.My new engine does have p.c. seals though as thats just what the builder did.

[A.W.Dille]

I had teflon seals installed in my 670 heads about 8 years ago and love them. Haven't had any problems that I can speak of especially since my GTO was a daily driver for 3 years.

[74t/a]

A positive viton seal is a much better choice for the street. The all teflon seals will let oil pass, and also are hard on the valve stems. I have seen them wear the valve stems beyond belief.

I have gone to a metal clad/viton seal for all my street engines with excellent results.

[rexus31]

Thanks for the input. Bill Baker and I swapped out the teflon seals for viton today.