While the 'hot rodders" might consider this question mere "mental masturbation", those of us married to the original, obsolete system might be interested:

Recently, someone mentioned that a longer duration camshaft would reduce manifold vaccum, and implied a resulting loss of spark advance on a Loadomatic distributor/carb combo. If the signal to the diaphram is a mixture of manifold/venturi vaccum, then the more important performance factor (acceleration) would depend on the venturi signal, as manifold vaccum would seem inconsequential at WOT. In fact, one of the problems with the LOADOMATIC system when initial advance is set by ear is too much advance at cruising (no load). If an early distributor was "race tuned" on a SUN machine (weaker springs), wouldn't the reduction in manifold vaccum actually cure the rough-running-at-cruise problem without affecting the enhanced, venturi-driven performance curve?

6 VOLTS/POS. GRD. NW INDIANA