Ant I see what you are trying to do with getting cooler clean air to the carbs. The Major problem is a backfire or hicup and you get a fire ball into where you are sitting.
If you like it hot or possiblity cooked. good luck. Have you looked into using the front air ducts that would go to the brakes instead for air inlets over even branch off them or make new inlets in front of the radiator. Messing in the passenger compartment is not a safe idea. Rick L.