Ported Vac or Manifold Vac

Do you know which vacuum canister is in the distributor ?
There is a number on the arm . And do you know you can change when it starts advancing? You will need a mighty vac to figure it out.
It is important to know regardless of which port you use . Maybe you have already mentioned this but what is the curve like ?
A properly setup distributor makes a big difference in power and driveability.