Mustang II rack to GM intermediate shaft issues

[Woodbutcher]

So I'm at the point with the build on my '56 Chevy shortbox that I am tackling the steering. I have a Mustang II rack mounted on a TCI cross-member and a Buick Regal tilt column in the cab. I picked up a new looking collapsable intermediate shaft from the auto-recyclers today for $20 in perfect shape, out of an '02 Astrovan. Damn, it looks perfect - small and sleek like a more expensive Borgeson joint system without the price, and, not as big and cumbersome as some stock systems like the S-10 shaft, etc. It has no rag joint, but has two universal joints. One end slides onto the end of the column no problem, being a GM product I had hoped as much, but as I figured the other end does not match. The mustang rack does have the 3/4" splined shaft and the intermediate shaft does have a 3/4" splined hole, but either the number of splines is different, or the flat side of the shaft isn't the right size/shape, etc . Everything else looks great and I'm 90% of the way there. Any ideas out there??

BTW, the truck will instantly fail the pre-registration inspection here in BC if we do ANY welding on steering components, so that is out of the question.