I went to that website that cowboy bob reffered me too, and that website shows where to look on the block, but i couldnt see the casting number were it was saying to look.

 

sounds like you may have one of the mexican big boy blocks. . .these are actualy heavier and more durable than any other block due to the metals used.

 

Thats what i was reading on that website it had a lot of good info about the "53" and the mexican big boy block, stuff i have never even heard about before. Lol kind of weird though the mexican block is better than the brazilian block.