My home inspection of Speedmaster heads

i went back and watched video again in there was no vavle seals on the head
You say that these seals are magnum style seal........so are they a positive seal that slide on the guide with a spring to hold them there or are they some sort of umbrella type seal?
Look in the box of valves, springs, keepers. The seals are on top of each valve. 6:22 mark