Disc brake upgrade help

[MyDream55]

Hello.. I recently purchased a power disc brake upgrade kit from Tuckers Parts. It comes with rotors, calipers, spacer, bracket, power booster, master, and prop. valve along with all hardware.

The part im stuck on is instructions say to use existing hub. I had to remove rivets to separate hub from drum. It then says to place rotor behind hub and insert from rear. The kit also came with new studs. I am assuming i have to press out old studs also.* My other issue is I am trying to fit my hub over my rotor as stated, however the hub does not go in flush with the rotor (the rear of hub is just too big for rotor opening). I dont see how the studs are going to fit behind rotor (as instructions state) and through hub if the hub is not flush against the rotor.

Has anybody else seen this issue or am i missing something here?

By the way its a 1956 3100..

Thanks