I'm sure you already know this, but 50'sKid had a good video on the diff swap. And starting at 19:23 in his video, he does a good job showing how easy the output flange swapover is, so you can keep your existing shaft bolt pattern/output shaft
I miss 50'sKid video's. I learned a lot from him
https://www.youtube.com/watch?v=k0W5YOQTT2o&t=182s