65 Barracuda Brakes... Help

You could always leave the rear alone and put the factory disc brakes in the front. Not as many wheel options that way but you wouldn't have to mess with the rear at all. As for finding 4 1/2" rear axle shafts for the early 7 1/4 rear, I haven't heard of any but maybe there are some out there. I don't think I'd put any money in one of those rear ends though. Get an 8 1/4 out of a '73-6 A-Body if you want an easy and relatively strong bolt-in unit with the big pattern. Go with an 8 3/4 if you need the extra strength but it will be more costly.