'68 fastback 440 wiring harness to suit
MSD Wiring Instructions.
I don't think MSD is still supplying the terminals and plastic isolators pictured above. It was done wired this way because that way because the early systems would die suddenly and this provided a quick means to use factory system or a second box as a backup.
The battery in the drawing is representative.
Heavy red must connect to a main power source. Battery feed at the solenoid, or Alternator batt terminal are also good locations. Heavy black is best connecting to the engine block or heads.
Orange and black must connect to the coil.
On/off red can connect to the igntion run anywhere in that circuit. It draws very little current.
Here's photo.
Another way to connect the MSD on/off t othe original ignition wire is like this
Finally, a piggy back on the ballast resistor is another simple way.
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Getting fancy for the MSD power feed.
This way the ammeter only shows power into or out of the battery.
It also connects the MSD power closer to the power source.
The black 12 ga wire going through the firewall goes to the ammeter black terminal.
This creates a parallel feed to the main splice and for battery recharging.
I did this because (a) the original feed through the bulkhead had some heat damage (my fault) and (b) because I had the instrument panel out for restoration, so it was a good time to do it.
Its a fair amount of work.
MSD Wiring Instructions.
I don't think MSD is still supplying the terminals and plastic isolators pictured above. It was done wired this way because that way because the early systems would die suddenly and this provided a quick means to use factory system or a second box as a backup.
The battery in the drawing is representative.
Heavy red must connect to a main power source. Battery feed at the solenoid, or Alternator batt terminal are also good locations. Heavy black is best connecting to the engine block or heads.
Orange and black must connect to the coil.
On/off red can connect to the igntion run anywhere in that circuit. It draws very little current.
Here's photo.
Another way to connect the MSD on/off t othe original ignition wire is like this
Finally, a piggy back on the ballast resistor is another simple way.
----------------------------------------------------------
Getting fancy for the MSD power feed.
This way the ammeter only shows power into or out of the battery.
It also connects the MSD power closer to the power source.
The black 12 ga wire going through the firewall goes to the ammeter black terminal.
This creates a parallel feed to the main splice and for battery recharging.
I did this because (a) the original feed through the bulkhead had some heat damage (my fault) and (b) because I had the instrument panel out for restoration, so it was a good time to do it.
Its a fair amount of work.
