Alternator ID and connections needed

This is on a complete rewire job for a 91 5.0HO into a 57 Ranchero. I need help identifying this alternator and wiring connections. I've searched the internet for pics of it with the wiring connected to it without any luck. Other than the plug there is only one threaded point that's not insulated from the body so I assume that goes to ground but can't figure out the connection for battery charging or the 3 pins in the plug. Thanks in advance.

Here are a few more. I misspoke earlier, there are 3 more pins recessed in the outer casing 90degrees from the 3 pin plug. I put a bolt in the threaded connection to locate it. Sorry that's the best pick I can get without removing other items but if it helps, I will remove them.