Engine sputtering at about 65

i wouldn't change the distributor unless it's faulty, or a points dist.

is it electronic? if so maybe just put an MSD streetfire ignition box on it.

if the motor has a stock camshaft in it then, the factory dist timing is fine. which will be about 28-30* mechanical advance most likely, so you set the initial timing around 8* advanced, adjust your idle mix on the carb and set idle speed. on to the next thing...