disk swap on '74 or keep drums?

I have SBP, so the stock discs from 73+ would require new wheels. As I understand it, switching to the 8 1/4 rear would be the simplest way to swap the rears to LBP as well. However, installing a 8 1/4 rear (assuming I can find one) would involve shortening the drive shaft. It all adds up to a project that is really beyond my capability.

If I do the swap, I'm leaning toward the KH setup or an aftermarket SBP kit so that I don't have to mess with the rear end or buy new wheels.