8.75 A body U joints?

i have a 68 dodge dart with the 7.25 or 8.25 diff (don't know the difference) and im trying to upgrade to an 8.75. i found one with 3.91's that needs a rebuild and axles. what u joints does me slant car use? with the right yoke on the 8.75 will it just bolt up?? driveshaft modes??