don't have a picture here. but can make one tonight.
It's exactly like your cable that goes from battery minus to block. Just that it doesn't go to the block, it's screwed into the chassis of your car.

You can do the following:
take a set of jumpleads. Take only one side of it (as in one cable of the two). Lets say the two black connectors. connect one of them to the battery minus post and the other clamp somewhere on the chassis where you have a blank spot. or to a screw that goes into the chassis. (beware of rotating parts when you run engine).

If that solves your issue then you know this ground strap is bad or missing

 

I'll try it tomorrow. Was going to look last night to see what all grounds I have but was busy getting the boys to and from church.

I am taking a day off tomorrow because my boss is hounding me to use up some of my vacation. Have several honey do's around the house but also going to run across town and look at an exhaust set someone has for sale. Somewhere in there I should be able to play with the Stang for a little while.