I would recommend you go to some shows and meet some people.. There are many different bloodlines that are not over weight, and each have their own traits.. There are many variables to consider when picking.. what are your desires? your goals? and why a game bred dog and not just a athletically built one?? just curious ..
That is why when I sell a pup, they do not come with breeding rights. 9 out of 10 (or more) people who breed "Pit Bulls" do not know what a Pit Bull is. Most are mixed now a days.
Good luck on your search. They are out there. I would go ADBA registered from someone you trust.
There was a rescue mix in the news who bit a woman doing an interview. Yet all the comments were calling it a "Pit Bull". Its just the way it is.