Hey Josh,
I was told that not all small blocks are the same when it comes to the mounting bosses for the clutch linkage z-bar. Some small blocks have the boss(es) for the linkage and some don't. It should be about where you might expect. Inches above the oilpan and forward a few inches of the back of the block. It's been so long since I've seen them that I can't be too accurate in their location.
The blocks that have them can be used with either an automatic or a clutch. If they don't have them then you must modify or maybe use a hydraulic clutch.
Someone here will probably help you out.
Good Luck, Rick

I feel like I'm diagonally parked in a parallel universe.