Stainless steel is non-magnetic, I'm not sure about the oem valves, I'll check tonight when I go home & let you know.
I like setting a cylinder at TDC, compressing the spring & seeing it with my eyes, it eliminates all doubt. Once you get a valve cover removed, and if you have the spring compressor, its no big deal. Just make sure you're at TDC, so if the valve slips, it doesn't slip out of reach. DOH. Some guys remove the spark plug & stuff rope in the cylinder before turning the cylinder to TDC, the rope crams against the valve, so it cannot drop. Running air into the cylinder would also hold the valve up.
Your friend on the DTBB, George
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