Pull the fan belt to stop the water pump and the charging system, and see if the noise goes away. If not, it's probably the timing gears. Stovebolts are prone to have a humming noise caused by the bevel gears on the crankshaft and cam. While the belt is off, check the water pump and generator or alternator for bearing noise by spinning them by hand.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!