Look at it this way. As the motor and blower spin they create heat. The engine has oil and water in it to cool the parts. The fuel also lubes the the parts it passes thru. If you have no fuel going thru the top of the blower it has nothing to lube or cool it. Not that it can't be done but I think the clearances in side the blower would have to be very loose to acount for the heat change and no fuel to lube and cool the rotors. Is there a reason why you don't want to run injectors above the blower. If I remember right enderle told me that buy having port and hat nozzles you will gain 40% more tq.