Unidentified part 55' f100

Cant find this part any where online. Every other part I can think of is accounted for.

Connects to alternator, 3 wires., 4th goes to coil.

 

http://www.motorcityreman.com/moproe8r.html

 

Awesome Thank you. can you buy an alternator with this built into it?

 

I would think so ,not up on ford but gm 73 and up were internal reg.

 

Altenator is not spitting out enough juice. Removing it to have it tested. Not sure if its the regulator or Alt. I would liek to get a larger AMP alt, like the 60amp is 29.99 vs 40amp is 49.99. Not sure how that affects the regulator