Depends on how large of a u joint you want, some dana 60 & 70 have 29 spline, if you want the larger 1350 or larger u joint.

Haha I have a idea (scary, I know)
That pilot, just drill and tap it, get the slip shaft just cut it down a little, slide it over and put a grade 8 bolt and washer holding the yoke on.
Or don't cut down and use a 6" long bolt,might have to put a tack weld on bolt head and washer so there is not chance to back out.
That work, hahahaha
Try that at 160 mph at 7,000 rpm