Part Number Location

Never seen an actual part number on a driveshaft. Maybe when they were brand new there was one stenceled somewhere but after a few years out in the elements, they are long gone. The ends have numbers cast into them but I think that number is just for the end piece and not the assembly. A measurement will tell you which car a particular driveshaft is for. It would be rare to have an A-body with the big U-joints on both ends. I've seen some with a big on one end and small on the other though. Is yours a big block car or '68 Hemi car?