Is this what you have?
View attachment 477662
I've seen them with and without both the big hole and the top notch. Probably some specific tractor may need clearance for a bolt, etc, in that hole's position.
Bruce
Has anyone made a bracket to keep the trailer hitch (that piece with all the holes that fits across the quick hitch) from rotating? I want to use it to pull boat trailers and thought some of you may have already made a quick solution to this problem.
Thanks