Mine does the same thing but mine isn't near as loud as yours apparently is. Ive spent hours and hours chasing it and finally gave up even though it drives me nuts. :/ I just drive it hard and hope it fixes itself. LOL
Got one for my 66 after i realized how hot it got under the hood with a aftermarket turbo and how it was cooking my AC line. I can drive for an hour and lay my hand right on the blanket!
I raced a buddy last night with a p pumped dodge, he has a built trans, colt cam, oringed and studded head, valve springs, 4k gsk, 18* of timing, 5x14 injectors, a 64mm turbo, different delivery valves, and dual lift pumps, I walked him. :)
How far are you from Hagerstown MD? My truck has been loud and has a tick under load ever since I did my head studs and s366. Id love to hear yours and see if its the same sort of sound, if it wasn't so much work I would have re adjusted the valves already.