Question about TH350 in 72 C-10

[72bowtiestepper]

I am restoring a 72 C-10 short wheelbase stepside that I purchased without a engine or transmission. The SPID states the truck was orig. built with a TH-350 automatic & 350 smallblock. Was the trans in shortbeds the shortail or longtail version of the TH-350 in original trucks. Also, would like to know if either could be used with diff. length driveshafts, made to fit. The rear is a 12bolt (non-posi) if that makes a difference.
Thanks for your help guys !