Street and Performance Electronics 40025 Helix Power Tower Plus Throttle Body Spacer 1998-1999 Ford 4.0L SOHC Produces an increase of up to 8 hp / 10 ft lb of Torque & 1-3 miles per gallon Variable Venturi Aperture provides turbulence to mix the air/fuel charge for a more complete burn efficiency Computer designed chambers and channels specially designed to improve efficiency and air velocity performance Increased air-flow creates better engine cylinder filling, can be used with any grade of fuel for more power and economy Complete Kit includes all gaskets, hardware and complete instructions for an easy installation