black neoprene valve stem seals, easy Q

other than shallow ones for ex valves/deeper ones for intakes, is the fitment the same, in other words will the same press on ones fit any 5/16/8mm/3/8 valve stems? Thank you for your time.

I use them as "stem diameter specific". sometimes an umbrella for a 3/8" stem will work on an 11/32" stem. I like the umbrella snug on the valve stem because it's supposed to ride along with the valve. I use the same length for intake and exhaust. of course that can't be done on heads machined for intake and exhaust specific seals.

Yes with them being a snug fit I was thinking that they might be universal ex for the special machining you mentioned. If useing the tall ones on the ex also is a good plan I will incorporate that from now on.