with any factory distributor used on a modified engine, and even a stocker, one needs to get inside and play with the weights and springs.
every combination of the same components is slightly different, so using specs someone suggests will work, is just the STARTING point.
also be forewarned, this is NOT a 5 minute job..........
it takes some trial and error to get the right weight spring and weight calibration for your combination, THEN, you need to work on the vacuum advance curve.
just my personal experience with distributors over the many years. your mileage will vary.