1975 A833 od, any useful parts for non od boxes

Hmmm not sure about the input shaft, thought it might be different too. You can swap the whole set of guts from an OD trans into a standard case or vice-versa (assuming you have a large bearing case), but you can't mix and match components.

Why is it too bad? An iron case 833 OD is almost as strong as a regular 833, plus an overdrive gear to boot. Gear spread is a little wide, but they're still great for a street car. If it doesn't work for your application you should be able to sell it complete for a decent chunk of money, the iron case OD's are more desirable.