carb tuning help

Does your msd distributer have vaccum advance? If it does you can always run that off of manifold vaccum source to get a little more timing at idle and cruising speeds to help with keeping the plugs cleaner and fuel mileage.
On my 360 magnum if I just run my 16 degrees of initial timing with no vaccum advance at idle it idles at 195 and if I plug the vaccum advance in to the manifold vaccum port to add another 14 degrees of timing to the 16 degrees of intial timing it idles at 190 and it cruises much more smoothly down the highway.