Ignition timing can affect the power you get from your engine. The question is how much. You may be getting the practical maximum now. Opening the points will advance the spark (it will occur sooner in the stroke cycle) and perhaps ignite the fuel/air mixture at exactly the right point in time (depending on RPM) to extract the maximum energy for moving the piston. If you advance the spark to much, you will never start the engine, because the explosion will tend to force the piston backwards.
This was how broken arms from cranks occured with early autos when they forgot to retard the ignition. Early autos had manual ignition timing on the steering column.
Stay with the factory setting. You can still get 35 mph with a biturbo and a larger carburetor