[Spridgets] alternator conversion help needed

[ryan.kubanoff at comcast.net]

I am converting from the original lucas alternator to an alternator from a ford festiva. What I thought would be an unplug/replug wiring is not the case. Has anybody done this on a 71-74 midget? there are 3 wires from the wiring harness 2 thin and one thick. but there are multiple wire connections on the alternator. one nut for the battery, a 2 wire plug labeled S and L, and another small plug connector towards the bottom. 
Any ideas?