Sounds like you've successfully solved the problem. That picture is great, but aword of caution--make sure everything is bright metal where the high amperage connections occur.
Not too long ago, I replaced the battery in my '46 1-1/2 ton, and put a new cable to the starter stud connector and a new braided ground strap from the battery to the transmission housing bolt.
From long experience (well, not so long, really) I climbed in before I put the floorboard back in, "just to make darn sure" Ol' blue would crank up. Mashed the starter, and .....nuthin'.
New battery, new cables, battery shows full charge, so check the connections.
Yep! That bolt connection on the transmission housing had a oil film (caused by me) when I took the old strap off and wiped it just a little. Either I wiped it too little, or not enough, but just enough to muss it up. Really cleaned it, screwed everything back together, and.....ah! the sweet sound of success!
Watch those loose connections. Anything loose, or less than a GOOD connection means voltage drop. Voltage drop means heat. Too much heat means burning insulation. Burning insulation doesn't smell too good and can result in a very bad smell known as burned paint.
