I am no way responsible for any damages or injuries caused by doing these modifications.  WORK AT YOUR OWN RISK!!!!

How To Install A Header

This How-To is for a header install on a B16A block, other models/engines should be similar with some modifications possibly to/for the O2 sensor wiring. So lets get on with it.

Tools used for this install:
Ratchet sets: 3/8 and 1/2 inch with assorted short and deep sockets
Sockets needed:12mm, 14mm,14mm deep,17mm
Wrenches needed:12mm and 14mm
12 inch extension
Small screw driver
Pipe wrench (12 inch)
WD-40
Anti-Seize Compound/Lubricant
Breaker bar 1/2 inch
Jack stands or equivalent
Dry flat/safe work area

This is what you get in the box, header, a-pipe, all the bolts, nuts, gaskets and the instructions necessary to install it on your car. Start with lifting the car up about 10 to 12 inches so you can work under it, a lift would be really great but not necessary. Start with removing the heat shield from the manifold by taking off the 12mm bolts holding it on. Next loosen the 12mm nuts holding the manifold to the engine, but do not remove at this time.

Now go under the car and unplug the O2 connecter by pushing in on the tab on the side of the upper plug and pull up, then use a small screwdriver to push the tab in at the bottom of the connector to remove from the bracket. Spray WD-40 on the spring bolt nuts holding the cat to the A-pipe. Wait a few minutes for the WD to do it's magic. Then using a 12mm socket on the nut and a 14mm wrench on the bolt remove the two spring bolts. Now remove the two 12mm nuts holding the A-pipe hanger to the back of the engine, on the A-pipe I installed it did not have the back bracket to mount it back on the bracket so I also removed the bracket that held the A-pipe on too.

Going to the front of the engine, remove the 14mm bolt holding the manifold to the engine. Now spray the three nuts holding the manifold and A-pipe together with WD-40, again wait a few minutes for it to do it's work. Using a breaker bar with a 14mm (standard or deep) with a 12-inch extension remove the three nuts. Carefully lower the A-pipe to the floor so you don't damage the O2 sensor. You can now slide the A-pipe out from under the car. With that done it's now time to go back upstairs.

Now you can finish removing the 12mm nuts that hold the manifold to the head, and then remove the gasket from the head. You can clean the front of the engine block at this time if you want. Engine cleaning how-to is available on this site.

With everything removed and cleaned up now it's time to start installing the new parts. Start with the new manifold gasket, then put the new top manifold section on, apply anti- seize to the studs and using the old nuts put them back on, tighten snugly so it can't move. Sides note: If you have Air on your car, remove the one bolt that holds the line closest to the engine to the condenser so you have more room to slip the header in. Now remove the O2 sensor/wiring from the old A-pipe with a pipe wrench and put anti-seize on it before installing it in the new A-pipe (30lbs. torque). First put the two new o-rings gaskets in the front of the A-pipe, slide/move the A-pipe carefully under the car as to not damage the O2 sensor. When under the car you can now put the new o-ring gasket on the back of the A-pipe and lift to mate it back to the cat (it helps at this time to have someone help hold it up so you can install the spring bolts back in). Before installing the spring bolts be sure to put anti-seize on the threads, tighten the nuts snug at this time. Now go to the front and after putting anti-seize on the three 17mm bolts, hand start the nuts then use a extension and racket to tighten, installing the A-pipe requires some pushing/pulling to line the studs up, start with the outside bolts first.

After all the bolts are in you can then tighten them up, no torque specs were given with the instruction I got, just use good judgment, don't go overboard with tightening. With the front bolts done now do the final tightening on the two back bolts/nuts to the cat. Now you can hook the connector back for the O2 wiring back on the bracket, I had to bend the bracket down some as it was a little tight. Then you can connect the two plugs back together, you are now done under the car. Go topside to finish up with the nuts on the manifold, tighten them down and you are now should be done with the install.

Check over your work then lower the car and start the engine to check for any leaks, and then go on a test drive. After letting the motor cool down check the nuts on the head for tightness, then again a few days later. That should do it.