I've seen a lot of threads about what belt to use and well, I am not running my smog pump yet. So I went to put the belt on and what do you know, the belt meant for my truck TBI 350 (96 1/8" w/ A/C; w/o A.I.R) seems to work just fine.

Delco: 6K956

Gates: K060956

I haven't run it yet but it appears to be a good fit, the tensioner is about where it was with the smog pump and not retracted all the way nor extended.

Hope this helps.