Drop base for a 750 dual feed double pumper

You can buy about any aftermarket air cleaner from Summit or Jegs and it most likely will have the drop-base for a Holley.
Or you could buy this hat, and pipe an air filter to the front of the van, to escape the heat of the dog-house.

Holley 120-230 Holley EFI Carburetor Hats | Summit Racing