I had trouble too. Found one in a U-Pull yard close by. See this post-
http://67-72chevytrucks.com/vboard/s...d.php?t=831522
For interchangeability:
'73-'82 C10/20/30 are the same- GM p/n 6270303 - Rod, steering connector
'83-'86 C10/20/30 & '87-'91 R10/20/30 are the same- GM p/n 14067697 - Rod, steering connector
Not sure what the difference is between these 2 p/ns