fitting my frame

Has anyone had success fitting a Predator engine on a Huffy Cranbrook?

I am looking for a RAW engine, but I am skeptical on if it will fit my frame. The dimensions of the frame are (top)18" x (bottom)22" x (height)11.5". I don't know if I should get a slant angle engine or a regular engine. I am looking here for my engine. I have heard of that mounting it in...