As the guy who has tried many different carbs on a modified 261,it's my opinion the Holley Weber is way over rated.You can bolt on any properly jetted carb on your stock manifold and see a big improvement over the Rochester B or Mono whatever.
I've taken the model 1904 Holley single barrel from the 50's Ford 223 6 or 60's Mopar slant 6,fiddled the linkage to fit, bolted it on a 235,unreal improvement.A Carter will do the same magic and both of them need no adapter.
The single H/W's work well, but part throttle power is reduced for a slight gain at higher speeds, and it's gotta be the ugliest carb ever built
