Extreme Composites

170 Inwood Dr

Rockdale, TX 76567




Z78 Hood TBI Airbox Installation


Caution:  Ram air kit is not intended for severe wet weather such as flooding. Do not flood scoop with water when washing truck or any other time.  Excessive water in air box from any source will cause severe engine damage.


1.Trim air filter opening to fit a K&N air filter # 33-2056


2.Trim throat approx. 1/2 inch longer than pencil line. Turn air cleaner bolt so it does not interfere with fitting.  Test fit by closing hood with air box in place. Trim or sand until hood will close and air box is evenly spaced  1/2" from hood.


3.Drill 1/4 inch hole 4 inches down and centered on back side of air box.  Bend air filter bolt so it matches hole. Remove bolt from throttle body while bending. Fabricate bracket to hold front of box in place. It should support the front of the air box and mount to the front of the intake manifold. Use RTV silicone to form a gasket to seal air box to throttle body


4.Mark inside of hood and cut hole to match air filter. (a hacksaw blade works good) Cut open upper scoops and glue screen in place. Use fiberglass reinforced body filler. Attach a foam gasket to top of air box to seal to hood to air box.


5.Remove intake hose for the PCV System from the air filter ring on the throttle body. The intake hose will be on the opposite valve cover of the PCV Valve. 


NOTE: If this intake hose if left on, the ram air pressure can blow out your rear main seal.


6.Install a filter on the valve cover hole where the PCV intake hose was.  You can use K & N filter # 33-2050.