1969 C10 3 Speed Spline Count

[RMBillings]

So I have been searching all over to get a 100% answer to my question before I order parts. I need to put a new clutch in my sons 1969 C10 pick that has a 3 speed manual transmission. I am pretty sure that year came with a Saginaw transmission. I am trying to determine if that trans has a 10 or 26 spline input shaft so I can order the parts. All the different places I have search give both a 10 or 26 spline clutch option. I want to do the job quick so I don't really want to take it apart to find out then order the parts. Any help would be appreciated.

Thank you.