Watch Ebay, I had a 2.8 in a 79 Mustang and it had a 2 barrel Holley. Also check Europen links as they were a hot motor there with progressive two barrels and even 4 barrels. Arkabilly
I had an 83 Ranger that had a 2bbl carb on it. I don't think it was a "normal" one, but progressive. (it's been a while sence I had it.) Anyway perhaps you could make up a plate type adapter for it. I've made them before and they are not that hard to do. Or you might check into a universal type adapter, depending on what manafold you have. I would think a 350 cfm would work well in it, or even a 60's or 70's Autolite/motorcraft one off of a V8. Also you might want to scrounge around for a carb spacer from a V8. Try to find one without an egr valve in the back. Put that above your adapter, and smooth out the transission from one to the other, and the intake. Good luck!