If that is true, then this won't be difficult.
Disconnect the battery power ground by removing the negative battery terminal.
One 4 gauge wire goes from the big stud on the alternator to one side of a 125 amp fuse. The other side of the fuse goes to the battery side of the starter solenoid. Pre-fab 4 gauge cables with lugs already on the ends are available in most auto parts stores. Look for the starter switch to starter cables. The fuse & fuse holder may also be there too.
The power feed plug for the old alternator has two black/orange wires and one small white/black wire. After you are finished working with the white/black wire, tape the plug up good and secure it out of the way.
The white/black stator wire gets the insulation stripped back about 1 1/2" in the middle of the wire & cut in the middle of the stripped area. Then a short length of white wire with a ring terminal gets spliced on to the white/black wire. Slide on enough 1/4" heat shrink tubing on the white wire to cover the solder splice you are going to make. Next all 3 wires get soldered together & the heat shrink tubing gets shrunk. When you finish, the white/black wire looks like a "Y" with 1 white arm and 1 white/black arm. Connect the ring terminal to the small stud on the alternator.
Plug the 3 wire plug into the mating connector on the new alternator.
Add a 4 gauge ground wire running from the block to the chassis ground where the battery pigtail ground connects.
Re-connect the battery negative terminal and you are done.
This arrangement retains the stock wiring so if your new alternator ever fails, a stock 65 amp alternator can be swapped in without any problems.