Does anybody know what these things do where they can be puchased new or if there even needed?

Is this just another name for valve stem oil seal?

I've never heard of a "nylon shredder". Where are you reading this?

It sounds like he's describing the plastic part that sits on top of each valve. They're easy to break when you remove the valves from the head. I don't know what the technical name for them is, but if that's what you're talking about they'll come with a gasket set for the engine.

If thats the case, they are the valve stem oil seals. The ones in gasket sets are ok, but I got mine through MTS, and I belive they are made of viton? It's a rubber type plastic, that's supposed to never turn brittle and fall apart like the originals.

Do they sell the umbrella style at MTS? I have heard them called shedders, as they are made of nylon and shed oil off the stem! My shedders/seals are rubber with teflon inserts which is probably very similar to what he is looking at, they are not umbrella style.

To directly answer the question they can be found at partsamerica.com (Advance Auto Parts)

Thanks for all the replies I got my gasket set in today and they were the umbrella type valve stem oil seals supposed to be the premium seals that fel-pro sells I got the term "nylon shedder" from my 77fsm or the 68fsm I cant remember