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Stack Racing Upper Intake Plenum 4.6L ('96-'04 GT) - Installation Instructions

Installation Time

60 minutes

Tools Required
  • Flat-Head Screwdriver
  • 1/4 or 3/8 Ratchet
  • 10mm and 8mm Sockets
  • Set of Allen Keys
American Muscle
Shop Parts in this Guide


1. Open hood and disconnect negative battery cable. Remove the IAT harness, air supply hoses on intake duct, and intake duct using a flat-head screwdriver.

2. Disconnect IAC hose, PCV hose, and vacuum block from plenum. Also remove the TPS and IAC harnesses at this point.

3. Remove the two 10mm bolts holding the throttle cable bracket in place, the four 8mm bolts holding the throttle body to the plenum, and the vacuum hose on the rear of the plenum. When throttle body is loose from plenum, carefully rest it on the vehicle’s cowl panel so it is out of the way.

4. Remove the 10mm bolt and the 10mm stud holding the EGR valve to the plenum.

5. Remove the five 8mm bolts holding the plenum to the intake manifold and remove the plenum from the vehicle.

6. Once the factory plenum is removed from the vehicle, remove the two 8mm bolts holding the IAC valve on and remove it from the factory plenum.

7. Install the factory IAC valve onto the Stack Racing plenum using the two supplied Allen head bolts. Make sure to use the new supplied gasket for the IAC valve. Also take this time to press in the PCV vacuum hose adapter into the plenum. There are two sizes included, so you will have to determine which one you will need depending on the size of your vacuum hose. The adapter can be lightly tapped in with a hammer.

8. Install the Stack Racing plenum onto your factory intake manifold using the five 8mm bolts you previously removed.

9. Re-install the vacuum hose on the rear of the plenum, along with the throttle cable bracket and throttle body using the bolts you previously removed.

10. Re-install the two bolts for the EGR valve, and reconnect the TPS and IAC harnesses, as well as the PCV vacuum supply and vacuum block connections.

11. Re-install the air inlet duct, reconnect the air supply hoses on the intake duct, and reconnect the IAT harness.

Installation instructions provided by Stack Racing

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