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C5 Corvette Header Installation


C-5 Smooth Flow Header System Installation Instructions


  1. Disconnect Battery.
  2. Raise the car and support with jack stands.  A lift is helpful if one is available.
  3. Remove cosmetic plastic engine covers,  spark plugs, spark plug wires, and oil dipstick.
  4. Refer to Corvette shop manual and proceed with removal of the factory exhaust up to rear tail section.  Be sure to retain the factory manifold gaskets for installation of new exhaust.
  5. Remove the 2 engine mount nuts that mount the engine to the front cradle from underneath the car.  This will allow you to slightly tilt up each side of the motor with a jack to allow more room for installation.  With the stock exhaust now completely removed try and secure all wires that appear may be close to the new headers  (Dismount front o2 sensor connections from frame and zip tie back to allow them to reach new o2 sensor bungs).  Also, check the leads going to the starter, these wires should pulled as close to the motor as possible before they go back and turn out by the firewall.
  6. Start with the RH (passenger side) header.  With a piece of wood between the jack and right side of oil pan slowly jack up the motor so it is tilted.  Be careful not to jack up motor too far so that it contacts firewall.  Have gasket ready and install the header from the top of the car rotating it down into position.  If ignition coil packs interfere with the header simply unbolt and lay out of the way.  Install header into place, and install one bolt loosely to keep it in position.  Return under car and install o2 sensor snuggly, they can be tightened firmly after the exhaust is completely installed.  Now is also a good time to check your starter wire clearances.  Install the rest of the header bolts (do not tighten any header bolts until all of them are in place) .
  7. Proceed to the LH (drivers side).  Lower jack, move to drivers side of oil pan, and jack up to tilt motor the other direction.  This side header may be installed from underneath the car.  Work the header up into position and have someone install a bolt from the top of the car so it does not fall back out.
  8. Tighten headers.
  9. Proceed to the rear of car and install muffler tail section if factory mufflers were removed.
  10. Bolt x-pipe to mufflers using new gaskets if supplied, and support with jack if needed.
  11. Slide hi-flow catalytic converters into the x-pipe.  Take note that the o2 sensor bungs are located in different places in order to accommodate different length o2 sensor leads.  Loosely install two 2.75” stainless step clamps to fasten (do not tighten yet).
  12. Move cats forward and slip over headers.  Install two 3” step clamps.
  13. Your new exhaust should now be in place.  Tighten all clamps (torque clamps to 50-60 ft. lbs), and o2 sensors.  Re-install and tighten coil packs and spark plugs if removed.  Re-install plug wires and oil dipstick (early models [1997-2000] should install enclosed late model [2001-2004] dipstick).  We recommend using a high temp plug wire with fiberglass outer sheath.  We have these available upon request.  Tighten all parts to factory specs.
  14. Re-connect battery
  15. Drive car 5 miles or so and jack car back up.  Re-tighten all clamps, and inspect for wires touching exhaust.


Packing List:

  • 1 pr Headers
  • 2 Random Catalytic converters
  • 1 X-pipe, 1 package of header bolts
  • 2 stainless 3” step clamps
  • 2 stainless 2.75” step clamps
  • (1997-2000 systems will include a late model oil dipstick). 


For Technical Support Call
Melrose (815) 758-2783