Timing /6 without advance port of the carb working correctly??

I contacted Mikes Carburetor Parts and asked him what he thought. This is what he said.

"Some engines, starting in the 60's, had full vacuum to the distributor. Ported vacuum signal for the distributor advance came from above the throttle plate at idle. As the engine speed was increased, incoming air rushed by the now open port and created a vacuum signal. This signal would advance the timing 8 to 12 degrees. Starting in the mid to late 60's some manufactures modified the distributor curve and camshaft to create less emissions and along with these modifications came the full vacuum signal to the advance! You need to research this application to determine if you need full or ported vacuum signal. If ported is required, then you may have the wrong carburetor. I can install a ported circuit in most carbs buy drilling a small circuit above the throttle plate. You can also do this about 1/8" above the plate at idle position"

Hopefully this helps
Thanks