318 LA-Valve Stem seals pict needed!!

You will find the long rubber umbrella seal, a short rubber umbrella seal (long is intake, short is exhaust), and a positive type rubber seal that presses over the guides (Intake in later models) in various factory heads. Then there's teflon and viton, both of which require the guide boss to be milled slightly so the seals fit without splitting, and get used on intake and exhaust sides. I've used the positive type rubber ones as upgrades on the intakes of many earlier engines with no troubles.