There's also the Pond aluminum block....... 427 Ford FE Type Engine, Pond Racing a very nice block. And there's also Shelby which is a bit more $$$ but hey it's only money.

Genesis does cast iron blocks on a more frequent basis. But also does aluminum. Normally Genesis is the go to for iron and Pond or Shelby for aluminum. If this is something your thinking about now or in the future buy it from a well known FE vendor like Keith Craft or Survival. And have them do the machine work. Besides some QC foundry stuff there's a pretty good laundry list to do on these blocks. These vendors know what to do and back it up.