Upgrading my 340

I'm having problems wih the page loading. It keeps resetting. But I think I read enough to understand what you mean. I think this boils down to just how much the engine is eating rather than carb size. I do not see a carb as a limitation as you putt unless it is pulling to much vacuum under load. (W.O.T.) IIRC, (LOL there....) a bigger carb is needed if it is pulling .7 or .5 on the vacuum gauge at WOT.

Considering carbs are rated at a vacuum draw of a set amount, how often does the carb pull that much vacuum? It varies as you stated and I agree. But it is the overall size of the carb that has to be choosen for the intended purpose at hand. To this end, not to add to the mix, but, this is the reason I like certain carbs for certain jobs. In example, the TQ or AVS for a dual purpose machine. Holley's for a race effort. The Holley has many different cfm sizes available to suite the need. The TQ is super flexible and the AVS only has a few sizes. So a short coming is hard to avoid sometimes, cfm wise. Theres worse things ..... than a carb to small.