I would figure it at about 250 cfm/carb or 750 cfm. I do not have bench flow data to back this up. Maybe someone like carbking can give a more accurate answer. I am not familiar with the 348 tripower setup. I assume it uses 3 small base rochester 2g carbs like the 57 and 58 olds and pontiac v8s. Pontiac went on to use 1 small base 2g in the middle and 2 large base 2g carbs on the end from 1959-1965. Pontiac changed again to 3 large base rochester 2g carbs for 1966, the final year of pontiac factory tripower.