Is there a specification for magneto resistance mounted on the engine? Taking a reading from the output post to engine.
The resistance is so low that any measurements will be fairly meaningless. The resistance is a fraction of an ohm. The test leads will probably have more resistance.
All an ohm meter is good for is to see if the magneto or the connections to it are not open circuit.
Unsolder the wire from the ground rivet.
Measure for continuity from the mag post the the end of the chain of coils. This should be a low reading.
Set the ohm meter to the highest scale. measure from the mag post to the mag frame. this should read as OPEN.
The resistance is .5 ohms. Reference Fahnestock. Without magnets in place, Ford technical article suggest, with volt meter and amp meter in place in circuit with coils, passing a 6 volt dc voltage through the coils the amperage reading should be 12 amps DC. E=IR.