c-10 396 w a 3 on the tree??

[wiggins]

Would GM have buckled a three on the column with a 396? Is this an original set up? I been googling and reading all day and I cant figure it out. I expected to find a chart for the two letter engine code that would give me an answer but Ive had no luck. Ive also noticed that the tranny is not mentioned on the glove box spid unless it was an automatic. Does this sound correct? Lots of questions, thanks for any help.