The distributor does not have to be in
any particular position for the engine to operate. In other words, the cap can "point" in any direction and you can make the engine run.
What is crucial, however, is that the rotor is properly oriented with the cap.
Since the cap only fits one way on the distributor body, you will have to rotate the distributor body until the cap is pointed in the "right" direction. By right direction, I mean any direction where the cap does not hit anything and you have good access to the wires.
To rotate the distributor body, you can just loosen the clamp-down bolt next to the base of the distributor. You can then rotate the body to any orientation you wish.
However, you must then rotate the rotor by a like amount. To do that, you will have to take the distributor clamp-down bolt off, and pull the entire distributor body up by about an inch. This will free the driven gear at the bottom of the rotor shaft from its drive gear. Then you can re-orient the rotor by the desired amount and re-seat the distributor.
Note that because the gear is helical, the rotor shaft will turn somewhat when you re-seat. You'll need to take that rotation into account when you do this.
But I would only advise doing all that if absolutely necessary. If the cap doesn't contact anything in the "wrong" position it's in now, then just route the #1 wire to the #1 cap terminal, #2 to #2, and so on. Assuming the wires are long enough, you should be fine. Of course, this also assumes that the #1 wire went to the #1 cap terminal on the old cap. If the previous owner had done some creative re-routing, you will have to follow the same pattern on the new cap.
Pete