Itll never gulp 390 CFM but that little carb is pretty versatile. You can alter the springs in the secondary well and have them open when they're needed, but I bet its not too often. a paper clip on the actuator rod is an indicator of how far they open.
"....Let assume that we are going to upgrade a 225 CID engine is going to run at a maximum of 5000 RPM. With 100% volumetric efficiency (VE), we will theoretically need 325 CFM but, since there are pressure drops in the induction system, we will only need 244 CFM with a VE of 75% and 276 CFM at 85%. .."
Carburetion
