Charlie, best best is to find a local starter/alternator shop and have your original rebuilt. The mini starter that GM used is actually a very good starter; lasts a long time and has more power and less current draw than the larger starters. Yeah; they do start to drag when they're wearing out, but any decent shop can rebuild it for anywhere from $50 to $100 or so depending on how bad it is.
I'd seriously caution you against trying to rig any kind of incorrect starter as the usual result IF you can get it to work is - damage to the flexplate, damage to the starter, and worst of all - damage to the block on the starter mounting pad and the starter bolt hole threads. You don't want that; trust me.