This motors ideal timing 38' total, anything less is a loss of power on this motor. I idle at 30'
I know about vac advance and mechanical but had to remove the centrifugal weights to use the MSD timing box. Its their suggestion to lock the dizzy only because the msd computer does the timing.
All that aside I dont yet see why using the vac advance to give me my full timing is a bad idea. I know its not being used properly. Im using it more as a 'full advance' after startup with no regards for fluctuating engine vacuum