Teflon is said to be for race engines and viton is the better stock replacement.
What do you think I should run???
Viton or Teflon?
Seals like Pioneer OS-966 spring loaded viton rubber in steel shell is the best seal to use (.500" guide OD and screw-on threaded OD with Atlas seal pliers)
or Comp Cams viton seals or other brand seals are very much superior to solid White Teflon seals
Seal Ranking (as far as Lasting/Endurance and actual sealing/oil control)
1st = Viton rubber (spring loaded, in steel shell)
2nd= floating Teflon ring in rubber shell
3rd= white solid Teflon seals
4th= Umbrella and Viton rubber umbrella
every ProStock Car or the Old ProStock Truck heads i've seen
have nothing but screwed-on Viton Rubber / spring-loaded valve stem seals ...never seen any of these type heads use solid white teflon seals
the guide OD is machined, and then Thread-Cut for a Screw-On seal with seal pliers ..instead of press or knock on seals
for ProStock w/Triple Springs , Pioneer and Comp offer smaller OD seals, but the OS-966 seal will also work