They look a little oversize than the Halibrands and Cyclones I used to use. Quick way to break the end plate is to put the Model A gears in a V-8 housing.
I had a set that would make 6.30's with a 3.78 ring and pinion, that were Model A, and I used a spacer. I forgot to use the spacer, quite the feeling in the stomach when I felt the gears strip. A buddy got this shot in real time !
You guys remind me of that tag line from those Farmers Insurance commercials, I say that in a complimentary sort of way. "We know a thing or two because we've seen a thing or two".
Youngster51, Please post pics of your QC as you get it apart and cleaned up. This may be the only record of a LOW Quickchange.