For the what it’s worth column I have witnessed with my own beady eyes and drove in and alongside a couple of folks running the OD setup including @Frodee They all liked the result. Only gripe is the reverse protocol. I am about to pull out my spooled 433s and am giving serious thought to doing the same.
Well add this to the what it’s worth column but for my 78, even though it is a 4 speed, they do make the gear vendors OD for it, thankfully. Heavily considering it or possibly doing an Nv4500 swap for the same reason. 1:1 and 4.56 gears currently.
My dart though, the t56 mag swap was far far cheaper.