Freshly built Combat, Cast pistons, stock aluminum push rods, non stock headlight ears.
No ringing. Actually sounds very nice, crisp and clean.
High Mileage 850, innards unknown, Stock headlight ears (new O rings and tight)
Ringing
Valves, Iso's etc adjusted to spec on both.
Only conclusion at this point is, don't think it's push rods or fin harmonics.
But then again, who knows....
The quest continues.....
BTW, don't remember ringing 45 yrs ago on my 73 850.