Camshaft Markings

Jim Bollman

I got a question today I didn't know the answer. A fellow acquired an engine with a cam that has etched on the back of the gear "281 us thermo".  My only guess is maybe it was from a ThermoKing version of the Crosley engine and it had a different cam for some reason.

I have never seen this on a cam, anyone have any suggestion of what he has.