2bbl with headers?

A four barrel will get better mileage almost every time. Especially in the case of the Thermoquad or Rochester Queerdrajet. Their primaries are much smaller than most two barrels. You have to remember, a two barrel, unless it is a progressive carburetor, opens both at the same time. That would be like a four barrel opening all four at the same time. I have never seen a factory stock two barrel V8 beat a factory stock 4 barrel V8 for mileage. Ever. Not once.

But regarding the OP's question, use the 2 barrel. It'll work good.