Internals are the big difference, clutch packs, valve body programming etc. I’d sell mine that is date code part number correct but wrong VIN, I looked long and hard to find it. If I had my original only ! My vin is 178072. Reward for it! Last know was San Jose area..
I do have a 71 hp trans that was rebuilt over a decade ago and has sat unused , dry with a 3800 stall converter, had some some goodies in it too..