Driveshaft question

Same driveshaft if you were running a 727 trans. If it had the small ujoint, a new driveshaft (or upgrade of the old) with the larger u-joints would probably be a good idea. You'll need to go with the larger companion flange on the rear too. This is assuming that you're gonna beat on that sucker. But then why put in a 4 speed if its not gonna get power shifted once in a while.