Keep your Ford all Ford, use a ford alternator.
This applys to wiring a late model, small case Autolite Alternator in the 56 ford car, I beleve that 54,55 and 57 use a similar harness but keep in mind that the 54 and 55 where 6 volt so other changes will be needed. These Alternators have a Brush holder/Voltage Regulator mounted on the back of the Alternator.
My choice is the 91 thru 97 Escort 1.9 engine as it has a split mount that makes mounting a snap. You will need to change the pulley to a "V" belt type to use this alternator. The pulley can be from just about any alternator as long as the belt grove width will work with your belt. I am sorry to admidt my pulley came from a GM alternator.
I would recommend removing the entire Generator harness back to the regulator as well as removing the original regulator. This will leave you with a 10ga Battery wire (may be paired with a 12ga that goes to the horn relay) and an 18ga that is the Gen Light Circuit. Insulate the 10Ga as you will not need it in the conversion.
At the alternator your best bet is to obtain the first 6 inches of the regulator harness from a salvage yard (most fords 80 to 97 with a small case alternator with 3 terminal intergral regulator will have this harness. If the Harness you obtain also has the Output lug terminal and 8Ga wire, Discard the wire and terminal as you will not need it.
This harness will have 2 connectors, 1 will be a 3 terminal that plugs into the regulator, the other connector is a 1 terminal that plugs into the alternator. When this harness is mated with the alternator you will be left with 2 unconnected wires coming out of the regulator connector.
A 14Ga Wire from the "A" terminal and a 18Ga wire from the "I" terminal.
Run a 14Ga wire from the "A" Wire to the Battery side of the Factory Starter Solnoid.
Run an 18 Ga wire from the "I" terminal to the Factory Voltage Regulator location, connect this wire to the 18ga Gen Lite wire that is left from the removal of the original regulator.
From the Output Stud on the Back of the Alternator run an 8Ga wire to the Battery side of the Factory Starter Solnoid. This wire will meet up with the wire you previously ran from the regulator "A" terminal, do not be tempted to make this
junction at the alternator and only run 1 wire. The "A" wire is used by the regulator to sense battery voltage and should be run separate.
In summary, you should have the following connected
(1) Alternator output stud with 8Ga wire to the Starter Solnoid (battery side)
(2) Regulator "A" wire with 14Ga wire to the Starter Solnoid (battery side)
(3) Regulator "I" wire with 18Ga wire to the Factory Gen Lite wire.
(4) Reguator "S" wire to Alternator "S" terminal (should be part of the salvage harness)
The "I" wire to the Gen Lite and a good Gen Lite bulb are required to insure that the Alternator "Turns On" at low RPM. The Output Stud should not be run to the factory harness, go directly to the starter solnoid, I would not want to push 70 Amps thru 10 ga factory harness, you will smoke the harness!
It looks like a lot but in the end it's only 3 wires, 2 of them going to the same place (solnoid) and 1 connection to the factory harness for the Gen Lite.
Mounting is simple, the top mount of the alternator is a split design that will stradle the original top engine mount. Use a 3/8 threaded rod with nuts and washers to set the alternator in position for proper belt alignment. The lower adjusting brace is from a small block ford, it's about 14 inches long in stock form. Cut about 4 inches off the engine side and drill a new 5/16" hole, bolt it to a waterpump bolt and your done. The lower brace is commonly avaiable at most speed shops in chrome as a dress up item for the 289/302 series engines.