Block identification question

Hey All,

I have a block which I need some help with identification.

It looks like an A series but it has 1200 cast into the top, (not
1100).  It also has removable side plates and a 2 inch main.  It was
supposed to have come out of a Midget, (I don't know what year).

Anybody have an idea what this might be??

Thanks,

Kevin