I am trying to find information/specs for the original driveshaft and u-joints that would have been factory installed in my '67 RO23 4-speed car.

The original driveshaft was not with the car when I got it so I am not sure what I should be looking for. The '67 parts book shows part number 2781955, 3.00" diameter and 50.27" long, for Hemi with 4 speed and 9 3/4" axle. The RO23 broadcast sheets that I have seen show the part number "99", which decodes to "special order". I am not sure what the "special order" means.

I would appreciate any information that would help me determine the dimensions and u-joint specs for this application.