IIRC Nicholson ran his 235 on #1, 3 & 5 carbs, with the #2 & 4 removed and the flanges blanked off, but that's a lot of work for a regular race-to-street change.
The problem is that leaving the "extra" carburetors alone with their linkage closed is that their idle circuits are still functional, and will both add gas and reduce vacuum to the other carbs.
