[Defender Chassis]

I got a set of headers in for repair and shot a video of how I tackle this kind of work.

https://youtu.be/C88e_i9tN2U

[Defender Chassis]

Part 2

https://youtu.be/d9CccgA0RBg

[sedanman]

Nice clean work but l do have a question. What changes were made to the car to allow undented headers to fit?

[Defender Chassis]

Nice clean work but l do have a question. What changes were made to the car to allow undented headers to fit?

To the best of my understanding, the original builder did not have the engine in the correct location. This has supposedly been corrected. In addition, when it goes back together this time the frame will be clearance on the passenger side.

[sedanman]

Dave Frieberger recently did a dyno shootout with dented headers and their engine made MORE power with dented tubes. Surprising results indeed.

[Poland308]

Golf balls are dented to reduce drag in the air.

[Rick_H]

Dave Frieberger recently did a dyno shootout with dented headers and their engine made MORE power with dented tubes. Surprising results indeed.

May have increased the velocity of the port, if the headers were too large...lots of variables when building headers, exh port efficiency, length of tube to first bend coming out of the port etc...

[John Chamorro]

Dyno tests have been done where there is a smaller tube inside the maintube. Say you are using a 2" header pipe, there would be a 1 3/4 tube inside for 4-6" as I remember. The inner tube acted as an air damn to take out the inversion of the exhaust pulses. They were gaining 5-10%. The dents probably do the same thing breaking up the inversion back flow.

[ldbtx]

Forget which header company it was, but years back somebody was making what they called AR headers. The AR stood for "anti-reversion".

[Harry72]

Do you mean timing the pulses like a two stroke power pipe?

[thatoneguy]

Headers are their own ball game in and of themselves. Very clean job and good video too.