There's 4afc's in carby, as far as I know that's the only twin cam 4a motor that was carby fed. Mind you it's an economy motor with a narrow head. You would be able to pick up a 4afc for next to nothing, if price is an issue.
4ag's have been turned into carb for racing purposes in japan, I don't know much about them, I think they ran twin webbers with trumpets. A search should bring up something. This would be the much more pricey way to go.