Hey guys, been putting my truck back together (1978 F250 Ranger) and cant find my records of what wires go where, i had trouble solving my issue with the wiring diagrams ive found online, hoping one of you guys with more experience could help me here. Thanks guys

 

There should be three wires for the alternator. The big heavy wire with the eyelet goes to the "BAT" or "+" terminal, the orange wire goes to the "FLD", and the white w/ black stripe goes to the "S" or "STA" terminal.
EDIT: There is also a fourth wire, but you can't see it. The mounting tab for the rubber strain relief is also a ground. If you pull the loom tape back you'll see that there are four wires going into the strain relief and only three come out.