The Ford flathead V-8's mounted the generator straight up on top of the intake at the front of the engine so I would suggest you concentrate your google search under the topic "Ford V-8 generator 1928 to 1953".
You could drop it at a nearby auto-electric shop and have them bench check for you.
Or like me just keep an old electric AC motor with a pulley under your bench. When you have the need just clamp the generator or alternator to the bench or in a vice and clamp the motor next it on the bench Wrap a belt around the pulleys and slide the motor away to tighten it. Then with a 6 volt battery connected to the generator ground and + to field measure the output when you full field the generator momentarily with a volt meter connected to same ground and the A terminal. If she's a good 6 volter she'll top out at about 8 volts in 2 or 3 seconds. If she keeps going higher then probably a 12 volter.