Right LPB. If you compress a spring, remove the keeper & retainer, you can see with your own eyes exactly what you have, i.e. single groove valve stem or multi-groove valve stem.
by the way, I checked, the tips of the Ford valves are magnetic, BUT, the tips of the stainless steel valves are magnetic too, because they have a hardened, non stainless steel material welded on the very tip, above the keeper groove, to make a more durable surface for the rocker arm to press against. So a magnet will not help determine which valves you have.
Oh well.
George
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