When used with an air intake pipe for an internal combustion engine, {HEAD ~ the device} allows {TAIL ~ more horsepower} and mileage to be extracted from the engine 
allows
When used with an air intake pipe for an internal combustion engine , { HEAD ~ the device } allows { TAIL ~ more horsepower } and mileage to be extracted from the engine
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH