You are right. The ballast resistor should be left in place if you are still using the points distributor

The MSD unit RED wire should be connected to BOTH the ON and the START wires

Where the MSD wiring diagram shows the IGN switch, it doesn't show BOTH ST and IGN wires connected. With some Datsun ignition switches it will work as shown but if you use both wires then all Datsun ignition switches will work

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  6AL wiring.jpg (77.59 KB)