If something was wrong in the radio wiring it would have melted something there or blown a fuse.  That wiring is WAY smaller than the starter wire.  No, something went wrong in the starter, solenoid, alternator, or battery would be by guess.  Whatever happened wasn't fused and it was a heck of a load. 

If the starter had been running wouldn't it have been making a heck of a racket though?  When you power the starter it engages, so I'd think it would make all kinds of noise, but maybe if it never disengaged from the flywheel? 

I did not hear any unusual noises, though my hearing isn't what it used to be and the car is kind of loud.  I do know the sound of the starter engaging with the motor running and it sure didn't make that sound.

Would the heavy cable running to the starter and the battery ground being in close proximity (touching) allow an arc to jump through the wire insulation?

I still need to crawl under the car to see if I can determine where the short started but the wire is badly burned and I may not be able to tell.  I also don't know if I will be able to determine if the insulation was worn off by contact by something to create the short due the bad condition of the wires.

By the way, this is not a stock 1965 starter.  It is a PMGR starter.

Michael H. wrote:

That changes everything... That means that the cable running from the solenoid to the starter is hot all the time and a smaller wire triggers the solenoid built onto the starter.

Make sure that cable doesn't have any nicks, cracks, or bare spots that could have gotten grounded.

Absolutely! I had a PMGR starter on my 89 Jeep have the solenoid stick and the starter ran but did not engage the flywheel. The started burned itself up before I could get the battery cable off.
 

Good deal... Glad to hear you found it before it caused a bigger problem.

Novi Rick wrote:

As you have surmised, my forensic investigation revealed a dead short in the hot cable running from the starter solenoid to the starter.  

The cable was wedged between the transmission coolant lines and the englne right along the edge of the oil pan flange.  Over time, the rather "sharp" edge of the oil pan must have cut through the wire insulation causing the short circuit and subsequent meltdown.  

Though I am a hack when it comes to working on these cars, I have to give an assist to the transmission shop that did an R&R on the trans for tucking in that wire nice and tight.  

Luckily, I didn't lose the car  to a fire and that it didn't happen on the freeway or any number of worse places.

And in a nutshell, this is the reason I don't let anyone else work on my cars.  People think I'm crazy when I tell them I rebuilt a transmission, swapped an engine, pulled the cab off my truck to do head gaskets, etc.  Then I hear their stories about how a guy fixed their rear and forgot to put oil in it, or they paid $16,000 for a full engine build then the truck died and the next mechanic tells them they got a set of junkyard heads with no machine work and one of the pistons was JB Welded back together!  I'm by no means perfect, but come on!  Also, the degree of perfection I want often means jobs take me longer than a professional mechanic.  BUT, my stuff rarely ever needs to come back apart anymore (not always so when I was younger), and I fix stuff that I find that's broken along the way to prevent further downtime in the future. 
 

Last edited by TKOPerformance (9/04/2018 4:52 PM)