The wiring harness on the passenger side of the valve cover contains circuitry for both a breaker point ignition (what your rig had originally), and normally has a separate non-identified black wire that is a switched b+ feed to the coil positive terminal that is "dead-ended". You also have the braided fiberglas "white" resistor wire which connects to the coil + terminal. The black wire on the coil + terminal now (sometimes it's green, color doesn't matter) is a "bypass" that applies b+ to the coil when the switch is in the "start" position only, that is run from the starter solenoid.
So for the prestolight electronic sparker, ya need a switched b+ when the ignition switch is in the "run" position, disconnect the resistor wire and insulate the end, keep it available for the future if ya ever wanna go back to the breaker point system.
Then hook up the positive and negative wires from the distributor to the appropriate coil terminals.
Simply ignore the white wire, that is used on "some" versions of "some" sii and fullsize rigs as part of the emissions system. Just insulate the end of it and tiewrap out of the way.
Later model pickalls that had the prestolight sparker oem, eliminated the "start" feed from the solenoid and had only a switched b+ feed to the coil to power the system. The ignition switches in those rigs also "bridged" internally so that only a single wire run was needed for both "start" and "run".
The wiring harnesses in any of the sii and pickalls May have several wire runs that are/were either deadheaded. Looped, or not connected to anything. Those harnesses were used on IH vehicles built and sold all over the world that had different equipment, or different "standards" to meet.
Don't forget to set the timing, that rig will respond nicely to the "power timing" method! The presto is an outstanding ignition system!!!
