Glad to be one of the many members to help. The
"droning" noise that you hear at 60-85 mph, might
be a simple exhaust issue. Question: Do you
have an exhaust crossover pipe somewhere between the header collector and 36" before the
inlet of the mufflers. Mopars seem to run better
and bit quieter with this pipe in place. The car,
while not an "all-out racer", needs all the
low and midrange torque it can get to run really
well on the street. This may help, along with
better flowing mufflers.