From a '76 FSM:
(L) Blue: Ignition Signal Feed from transistor ignition unit. Instead of being generated by the transistor unit above the fuse box, this will now come directly from your distributor with integrated transistor unit. But, to feed the tachometer you could backfeed the ignition signal using this wire AFTER removing the old TIU from inside the car.
(BL) Black w/ Blue: Ignition Coil Start power, with key in "START" position the wire has power, this bypasses the ballast resistor and allows for a hotter spark during cranking. You won't use this.
(BW) Black w/ White: Ignition Coil Run power, with key in "START" and "RUN" position this wire has power. This will feed power to the new distributor/coil unit.
The other BL probably goes to the ignition condenser.
ConorP
(L) Blue: Ignition Signal Feed from transistor ignition unit. Instead of being generated by the transistor unit above the fuse box, this will now come directly from your distributor with integrated transistor unit. But, to feed the tachometer you could backfeed the ignition signal using this wire AFTER removing the old TIU from inside the car.
(BL) Black w/ Blue: Ignition Coil Start power, with key in "START" position the wire has power, this bypasses the ballast resistor and allows for a hotter spark during cranking. You won't use this.
(BW) Black w/ White: Ignition Coil Run power, with key in "START" and "RUN" position this wire has power. This will feed power to the new distributor/coil unit.
The other BL probably goes to the ignition condenser.
ConorP
