"So, this will work, but only if the spring and diaphragm come from a distributor that was designed for a vacuum signal from a manifold and not the weak, venturi-vacuum signal from a carb..."
Isn't that what I said???
If you don't get a distributor out of a car (for this usage) that had an engine with manifold vacuum, you stand a very real chance of having that diaphragm fail, and that will not only deprive you of the desired advance, but will create a dandy vacuum leak that can lean-out your mixture an undetermined amount.
Cheap insurance... I'd do it, if I were you..
