Looks to be the typical plug gap for points, .030 to .035, you canuse for the most part whatever plugs you want that fit properly.
Ok, did a little searching, and got a little more for you, it is all the original Motorcraft parts from a user by the name of Numberdummy, liberated from another site.
C3TZ-12405-A .. Spark Plug (Motorcraft BTF-31)
18mm / 13/16" hex tapered seal / .028 - .032 gap setting
Fits: All 1964/72 330/361/391 engines.
For future reference, here's the rest of the tune up parts.
B8Q-12171-A .. Point Set (Motorcraft DP-12)
B7A-12200-A .. Rotor (Motorcraft DR-5)
C9AZ-12300-A .. Condenser (Motorcraft DC-13A)
B7AZ-12106-A .. Distributor Cap (Motorcraft DH-146)
D2PZ-12151-A .. Breaker Plate (Motorcraft DB-187-B) This is a one piece plate, it replaced the original two piece plate.
C5AZ-12192-F .. Primary Spring (Motorcraft MS-472)
C5AZ-12192-A .. Secondary Spring (Motorcraft MS-467)