I'm running into the same situation with my "upgrade"... I am dropping in a 331 Hemi with a Chrysler A727 transmission. I also questioned going with the one piece driveshaft but was advised to stick with the two piece unless I wanted to get in to pinion angle issues. From what I've been told, the front section will need to be shortened and the back section will stay at it's original length and sit at the same angle from the center carrier bearing as stock so pinion angle will not change.
Whether this is true or not is beyond me... that's why I am paying a guy who knows what he's talking about to take care of this part of the rebuild.
Lee
