I don't think think you'll break it with 650 HP, but there are many factors that go along with that statement.
We don't know which unit you have and it's previous life .. what, if anything has been done to it? But many circle track racers have used these successfully for decades. It does take up a lot of room, that and the cost makes the Ford 9 inch very popular. Maybe when you get some time you could share a few pictures of the car with us.?.?