Need help understanding what was done to my '63 Valiant convertible

Thanks for that info! This will prove helpful if I happen to break the two 7 1/4" rears I have. I don't think I will as this is not a high horsepower application. But you never know!
Doesn't take much to break a spider and/or side gear. /6's did it all the time after the gears got a bit of wear.