Vacuum Advance

PtownDart said

So,,,,,,,,,,,,,,,,I have a question concerning the distributor on my '70 340 Dart. It has an MSD Digital ignition,,,,, but,,, on the distributor,,, there is a vacuum advance dash-pot on it. Mine is not hooked up to engine vacuum,it was not hooked up when I got the car,,, I have seen guys go either way with the vac. advance,,,,,, for a Dodge 340,,,,, should it be hooked up for better all-a-round performance

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dashpot or solenoid?
Deceleration timing was the issue
The solenoid was a more sophisticated way to get the timing reduced at idle and deceleration.
For solenoid see here
Let's Keep It Clean (Session 270) from the Master Technician's Service Conference

As far as what you should do for your particular combination, first figure out what distributor you have and measure the advance. If its a quick and long advance afrom idle to 1500 rpm, then to use a non-emissions initial timing you will have to make changes to shorten that long advance.