I should have also mentioned that I see both NOS Motorcraft and NOS Autolite ignition switches on eBay. I assume Ford installed both brands at the factory.

Any thoughts on which is the best?

 

Can I take a wild guess that you're using a PMGR (Permanent Magnet, Gear Reduction) starter, a/k/a "Mini-Starter" or "late model starter"?

 

What kind of starter and alternator are on the car?

 

The starter and alternator are both CarQuest Premium brands.

Carquest Premium Starter 3124S
Carquest Premium Alternator Remanufactured Premium 7058A

I ran both CarQuest Premium starter and alternator since 1992 before replacing under the lifetime warranty from Advance Auto during the restoration.

 

Begin by looking at your battery cables and ground straps. Sounds ridiculous, but a missing engine to chassis ground strap will cause this issue. 1969 was the last year of the cylinder head to firewall ground strap.

 

I don't remember seeing that on the car. I will check to see if it came back from the restoration with the engine to chassis ground strap.

 

I checked and as you suspected there is no ground strap from engine to firewall or frame.

Sounds like this explains the ruined solenoids, starters, and instrument cluster voltage regulator.

I will get this addressed and post back once I get the ground wire in and install the new starter.

Would you recommend that install an NOS Motorcraft ignition switch just to be on the safe side?

I have replaced other aftermarket parts that the shop installed like the temperature sensor. The gauge reading was erratic until I installed a Motorcraft sensor. Now the gauge is always accurate.

Thank you!!!