How to Build Exhaust Headers

Exhaust Headers
  • 16-25 hours
  • Advanced
  • 250-500
What You'll Need
Lengths of stainless steel or ceramic exhaust tubing
Pipe flanges and bolts
Cutting wheel
Drum sander
Machinists dye

The exhaust headers are the part of a car engine that collects combustion gases and draws them out of the cylinders. Performance headers help the engine achieve better performance by reducing back pressure during the engine’s exhaust stroke. Custom headers are also installed for aesthetic appeal. If your vehicle has a modified engine the manufacturer may not have headers for it. You will have to build your own headers in this case. This job requires access to a wide variety of metal working tools. It also requires partial disassembly of the engine. Try to obtain kits with parts pre-fabricated for your situation. Sketch out a design and choose a type of exhaust pipe. Build to the design and check that it fits. Use good technique by cleaning all your cuts before welding. The project will take about 2 days to finish.

Step 1 – Design Exhaust Header

First, sketch out the layout of the custom header. Before building, you have to determine the angle, sweep, diameter, length, and composition of tubing that you will use. Obtain header kits or bend the pieces yourself. Disconnect the fuel lines and battery and remove the current exhaust header if applicable. Headers are made of stainless steel or ceramic. Some are stainless steel with ceramic coating. The ceramic provides thermal insulation and prevents rust but is prone to cracking.

Step 2 – Cut Main Tube

The first step is to cut the tube that will serve as the main exhaust collection point. All of the down pipes will feed into it from the engine cylinders. You will need two equal length tubes, on each side of the engine. Clean any cuts with a disc grinder. Bolt the flanges to the heads.

Step 3 – Connect First Bend

Attach the first bend to the end of the exhaust tube. You may have to flare it slightly to fit. Hold this piece up against the engine exhaust manifold to check the fit.

Step 4 – Cut Down Pipes

Cut down pipes to fit the remaining engine ports. Cut pieces of U-bends with a band saw and clean the edges with a grinder. Then, trim the other end of the down pipe to fit the header flange. Shape the ends with a drum sander. Tack weld them into place and mark the joints with machinists’ dye. Sketch out patterns of this design to copy it for the other side of the engine block.

Step 5 – Cut Holes and Weld Together

Cut through the tack welds and remove the down pipes from the header. Use a cutting wheel to make the holes for the down pipes. Tack weld the down pipes back on, and then clean everything thoroughly with the grinder one more time. Now carefully complete the final weld.