On the 289 motors, if it had a generator, it had a five bolt bell housing. If it had an alternator, it had the modern six bolt bell pattern we are familiar with. I put on the fans for a few years, the alternator job was two jobs before mine. The early alternators were 37, 42, 55 amp, then the larger size housing was 70, 95, or 105. We used mostly Ford alternators, the very early were from Leece Naville (sp?)
with some Motorola. Right before I retired in '98, the standard alternator was 100 or 105 amp for a Ranger.