GM Alternator Conversion

Installing a GM alternator in a 1972 Triumph GT-6 Mk III

New parts: 1 GM 7127 alternator (55 Amp Unit), 1 GM Alternator 2-Wire plug replacement end, 1 Crimp-on connector, Heat shrink tubing, 1-inch metal tube spacer, 53″ fan belt to replace the existing belt.

Overall cost in 1998: $50.00 including new bolts, belt, alternator, washers, connectors, & plug. Sure beat the heck out of a new/rebuilt cost of a Lucas Alternator with a lesser output.

Labor: Actually, it wasn’t that hard. Maybe about 1/2 hour to 1 hour, depending on skill level.

  1. Unhook positive cable from battery. Do Not Skip This Step!!!!!!!!!
  2. Unplug wires from the alternator.
  3. Remove Lucas alternator from brackets/mounts on the engine.
  4. Move upper swing arm bracket to a new location at the bottom front of the engine.
  5. Trim old plug off of wire & slip on heat shrink tubing.
  6. Crimp on post connector to largest of Brown wires (The one going to the Starter/Battery).
  7. Splice the brown/yellow wire to the terminal 1 wire on the replacement GM plug.
  8. Splice the remaining brown wire to the terminal 2 wire on the replacement GM plug.
  9. Heat up the heat-shrink tubing and seal the wires.
  10. Mount Alternator in place. You will need to use a 1-inch spacer block/tube on the swing arm bracket, this will necessitate a new bolt to mount it. Don’t forget the belt.
  11. Connect the crimped connector to the (+) positive mount on the alternator and plug in the GM plug into the alternator.
  12. Double check wiring, then re-attach battery cable.
  13. Enjoy the alternator’s output.

See pictures below for additional info. Unfortunately, the replacement plug came with 2 white wires.

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