I'm gathering all the parts I need to "Rebuild" my 1985 305 TPI and had a small dilemma.
I ordered a fel-pro head gasket set which includes new valve stem seals, and I ordered an additional set of enginetech valve stem seals.
The fel-pro set comes with 2 sets of seals
A set of these labeled as intake
And a set of these for exhaust
The ET kit comes with 20 seals in the same style as the blue one up top.
Intuition is telling me to use the blue style for both intake and exhaust but I wasn't sure if there was a reason not to.
The blue seals are the "positive" type; they grip the valve guide and stay put, and the valve slides up and down through them.
The others are "umbrella" type. They do exactly what the name sounds like: they stay stuck on the valve, and ride up and down along with it, and to the extent that luck is on your side, keep oil from dripping down the valve stem and onto the guide. USELESS AS **** ON A CHICKEN.
So yeah, use the blue type on all 16 valves. The reason FelPro doesn't spec em that way is because of the heat of the exh valve guides, and potential warranty problems. Regardless, they're still a couple of orders of magnitude more effective than umbrellas. You can buy a half-set of em by themselves if you don't have enough.
