Gary;Here is a link to the Y-Block castings, both Heads and Blocks. However, You may have to look at the crank flange to make sure.
http://www.ford-y-block.com/techincal.htm
By the way, I am also looking for a '57 Ranch Wagon or Ranchero project so if you find one and you are not going for it, please let me know.
Rono.