Just for grins, try changing oil to a straight 30 weight for a while. If the noise goes away or moderates noticeably, you're hearing rod bearing noise when the engine is at a "float"- - - -neither accelerating nor coasting. Stovebolt engines and water-thin oil don't play well together!
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!