What am I looking at for bellhousings? AND, if I wanted to go modern transmission, what am I looking for in bellhousings?

I found a company that makes an adapter for the 302 to a modern automatic, but, with no way to motor mount the jimmy on the sides, I'll have to do a front/bellhousing mount. I don't want 3 points of mount, nor do I want a modern trans hanging off the back of the engine all by its lonesome.