OK -- keep in mind that the mechanical advance curve that will be in it is a generic one. They will use the same kind of weights and springs as were used in the greatest number of factory units, and those aren't necessarily the exact ones you want for optimum spark advance in your car. It will work fine out of the box, but it may well not give you the most power for the fuel you're burning. Tweaking the advance curve is one of those "tuning" things that is required to get the most out of your engine once it is running well and reliably. It's the same thing as picking the right rods, jets, and hangers for the Qjet.
When you get the new distributor, check the end play on the shaft. It shouldn't be more than 0.010" - 0.020" -- the smaller, the better. Excessive end play will result in spark "scatter" as the shaft bounces up and down with the engine running, and that causes the spark to "jump" around because it's driven by the helical gear on the camshaft. It's another "fine touch" item.
