Just a wild idea I'm getting

The roots blower just works in a single direction, not like a whipple twin-screw design. Even if the rotors are helical, it's designed to force the fuel-air mix downward. Although, casting an adapter elbow/plenum would be considerably easier than butchering the blower case, especially the honing the interior and fitting the rotor vanes with oversized teflon inserts to insure compression. Not sure how much clearance that would leave...any more thoughts on this anywhere?