I have a 74 super, with a 71 engine, just got a new main harness,, but the alternator connection (on the new (stock) harness)is a round 3 prong conector, my engine has a flat type box on top of the alternator,, how do I convert it to work?? what connection is what? I have no idea!!!! any help appreciated!!!
The round 3-prong connector is correct for the '74 model. '74 used an external regulator, mounted under the back seat.
Your '71 engine has (apparently) a newer type alternator which has an "internal" regulator. It should have one big stud (B+) and one small push-on connector (D+).
The big fat Red/Wh wire goes to the B+ stud.
Now, you need a single wire to go to D+. Let's choose to use the skinny Red wire in the 3-prong connector.
Now, go under the back seat on the driver's side. If there is a regulator there, take it out. In any event, the harness should have skinny Red, Green, and Brown wires for the regulator connector. There should *also* be a skinny Blue wire in the harness leading to up front. Splice the Red wire to the Blue wire.
Done
You can see this schematically if you go to my web site and look for: "Wiring diagram for Type I cars with alternator."
Speedy Jim
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.