Originally Posted by 3hundred
Guys, for street only engines, positive valve stem seals or standard umbrella? MANY years ago I ran teflon seals, seems like IIRC, after ~ 10,000 miles the guides were worn out? Wondering if things are different today? If you've already got positive seals can you just remove them and install umbrellas?

TIA


That depends on the engine. Running any seals on a flathead is a bad idea.