If I'm not mistaking crate motors don't come with the stamping on that pad, but there should be a casting number on the back of the block where the bell housing bolts on the drivers side below the head. Should be something like whats in this picture.
http://ww2.justanswer.com/uploads/AS...e_location.jpg
When you get the numbers post em up and we'll look it up and see what you have.