Driveshaft Fitment Problem

[ClayW]

I am installing an M42 from a 1991 318is into my 1967 1600. I am also installing the five speed and driveshaft from the same car. When I tried to bolt the driveshaft to the new guibo, it seems to want to stop 2-3mm short of the guibo. I can drive the bolts on, but it just deforms the guibo. I gresed it up, but to no avail. What am I doing wrong? Any ideas?