Bing Carb

Lacking any orther Data Source ...

Using an online "Air Flow Rate through an Orifice Calculator" says,

A 36mm Orifice with a pressure drop of 1.5"Hg will flow 196cfm under Standard Conditions. (32°F at Sea Level)

Allowing a 70% Error Margin, lets call it ~140cfm.

That should at least put you in the ballpark.

It is important to understand that cfm has nothing to do with fuel. The fuel delivery circuits in the carb can be tuned to meet the engine's needs. But, the first step in choosing a carb is to get the right airflow.

Another formula as mentioned by Bill.

CFM = Cubic Inches x RPM x Volumetric Efficiency ÷ 3,456

Charles,

The Carb is more than capable of suplying the engine with fuel to Waaaay past redline speed even if you bored it out 20%.

The question is, "What do you really want to know?"