^^^. Lay out your old parts alongside the new parts to be sure the parts, or entire drive shaft assembly are the same length. The only thing that I an think of is your gear yoke is too long. I don't know the Bravo, but the Alpha assembly has very little space between the locking ring and the gear yoke uni. Your pics show much more space.
Pop the top cover to see if the gears are in full mesh. If so, I'd suspect you have the wrong yoke. If the gears are apart, you may have binding elsewhere. I always have to hold my mouth just right to get the driveshaft assembly started and slid home in the housing. There is very little clearance and any misalignment will bind things up.
Edit. ps. I assume you reinstalled the bearings on your new assembly (?). If so did you follow the procedure for setting bearing preload? On the Alpha you need to be sure the two bearing races are lined up perfectly. I use a large auto scroll hose clamp per the manual to make sure. I'm guessing there may be .002-.003" clearance between the bore and the race's OD. Any mismatch between the races will eat this clearance up and cause binding.
