Selection of Torque Converter and Rear Gears for Hot 340

I got it at a swap meet, at the close of the day for $50C in a F-body case.The guy said he was tired of hauling it around, so I offered the fiddy. To my surprise, he accepted it.
With the exception of the low gear, there is not one single gear in those two boxes (.71 and .73) that will swap over.
IIRC I bought two or three spares, or more lol,of those od boxes, and never saw another .71od.
The .73 box has a 20tooth od gear.I broke one of those as well. You know what happens when you are used to a 4-gear, and now you have 4.30s or more in the back? Hyup, Zing there goes another one,daymn she revs out fast with 4.30s.
I spent some time at a local wrecking yard. There I found an old school-bus with a number of od boxes, mostly Chevy pick-up stuff. But I never counted teeth; they had enough Mopar stuff in there to satisfy my needs.
I think I blew up three of those boxes: two od gears and the whole cluster drive on another. I think I still got a couple of good spares kicking around here somewhere. I'm done with those
If I had to guess, I'd say the .71 is likely a slanty ratio, while the .73 is likely a teener-box