The F67F-12B579-EA was used on Taurus, Ranger, Escort, the F37F-12B579-FA is for a '94 Ranger.
It's not about the MAF's ability to FLOW more air as in physically able to let air pass and not be a restriction, because what you are saying is true, that diameter is fine. What is the limiting factor is the MAFs ability to MEASURE the air. In stock form it 'pegs' when the MAF hits 4.7 volts (with a tune 4.998 volts). And with the combo you describe, the MAF will probably no doubt peg without something like a MAF.ia to extend the electronic range. To read about pegging, look in the tech section of our website:
http://www.lasotaracing.com/Late model maf.html
Don