i'm replacing the seals on the heads of a chevy 350. so went to napa and got a set of umbrella style seals which they said are better. now i've looked everywhere and can't seem to find any information on the installation. so any advice would be nice.

is the umbrella seal the only seal needed, or do i need the o-ring seal also?

and should i use the seal on the exhaust valve or leave it off due to the extra heat?

also, it would seem like the umbrella seal should go where the o-ring seal went but the spring retainer wont allow it. does it just ride on the valve shaft wherever it wants to?

i'm probably making this more complicated than i should but i want to make sure its done right the first time if at all possible. thanks.

If it were mine I would put positive seals in it. You may not be able too though without machining the guide to accept it. The umbrella seals just ride on the valves. Just push it all the way down when you install it. Use the small orings to keep the oil that puddles in the retainer from going down the valve. (compress it,install oring,then keepers. No worries I built tons of em like that. As long as your guides are good you should be fine.