If this is small enough it might work...

You could try trimming the stock filter housing to the edge of the filter itself.  This makes the stock ford housing look like an open element air cleaner.  If that doesn't work, you could always weld/braze the diamond shaped opening part of the stock housing to a more compact housing with the wrong size carb opening.  I believe the earlier Pintos had steel housings, so it shouldn't be too difficult if you have a wire feed welder.  Either that, or from what I understand, putting a small 350cfm 2bbl Holley on a 2.3 is a breeze.

 try weber carbs direct .com they have a listing that will fit the old holly weber not the one on the 1980 2.3 though hope this helps