He changed the ignition switch today and still won't start. I'm now thinking it's a bad Mallory module since we've checked everything but that. I also told him to check his ground from the block to the frame and the battery to the frame and to clean them up even it the appear to be good and OHM out ok. I'm going to try to get over there soon and perform the module test spelled out in the Mallory instructions.
Have I missed anything?
He should not have spent time and $ on the switch....
Oh well. Don't know where you/he are/is on this but getting back to basics...
Battery (-) should have 2 connections. One to body via the little pigtail bolted to the fender and one to the engine. There is no sense spending time grounding the frame (unless he has a trunk mounted battery and using the frame as the main battery (-), but I think you would have mentioned that).
There should be 3 Mallory wires. Brown, green, red. Unplug the distributor connector. With the other half of the connector in your hand, take a test light and see if it lights up with probing the red wire with the key "on". The other test lead should be stuck in the brown connector pin. This will tell you, you have both power and ground at the connector. The test light should also be lit when cranking the engine.
If that's okay, reconnect the 2 halves of the Mallory distributor connector.
Disconnect the green wire from the coil. Connect one test lead of your test lamp to the green wire. Connect the other end ( probe) of the test light to where the red wire connects (or try to stab it where the connection is made on the back side of the connector). When cranking, the light should be flashing as this indicates the module is switching ground on and off to trigger the coil.
If connections ok, but no flash, suspect module.
Let us know.