Wheres the ground wire go for a BBC? I noticed the SBC was on the alternator bracket but does it have to go there?

I use the bolt that goes through the bottom of the alternator bracket and into the head.

the ground can go pretty much anywhere it won't get in the way of moving parts,heat, and makes a good contact.
i used an intake bolt for mine

The block on mine, BBC or SBC it doesn't matter....

There's no 1 right place. Only thing that matters is if its to the engine block, and making a good connection (no paint, or rust under the cable lug (end)

I like to put mine down low and out of way/sight.