If you want some good technical info about how both the model B and the factory tripower setups work, then try looking at a 58-61 factory car shop manual. I used a '61.
Yes, there are basically 3 different sizes of B's. The difference is in venturi and throttle bore diameters. I have listed them before in other posts. 216, 235 & 261 are all different.
For the inexperienced, I would suggest trying to make it work with the carbs intact, like Ducky did, you may get lucky and not need to modify them.
Otherwise...
Remove idle screw and plug hole, or perhaps just turn in in all the way.
Remove power valve and the spring loaded ball above the main jet.
Plug vac source at the base of carb.
Make the throttle plate close perfectly.
