Here's some pics of a Mexican block sitting in our garage. This should help in identifiying your blocks. Not all blocks from Mexico are going to be Mexican blocks.
Mexican blocks can be identified externally by these two knobs on the front which can be seen when the engines are in a vehicle. See next two photos for this.
And in the car. This is a 337 roller Mexican block in my husband's Tiger. Note the big knob he's pointing at is easily visible.
This is what you'll see in the lifter valley.
This little 'MF' for Mexican Foundary is also visible externally by the distributor hole.
The part number on this block is D1ZM which means 1971. Any Ford part number with a 'Z' or an 'X' indicates high performance.
Last but not least, the bottom end with the heavy main caps. They also had thicker main webs and thicker decks as well as the higher nickel content. The internals were just standard junk.
Hope this helps.
info on 302 mexican blocks
