sptcoupe wrote:I don't know how many highly built engines I have had in my cars over the years. In fact, I think all but three of my motors have been highly modified, and all have had headers from the various suppliers that have traditionally made them available. Some have been better than others in terms of fitment, performance boost, etc, and none have been bad, but to be honest, most produce fairly modest gains that you often can really only measure on the dyno. They are a help, and the more modified the engine, the better the boost in performance, so I am not saying you shouldn't fit one as an essential part of your performance mods. After having done all the other work, you would be silly not to, and they will all improve performance over the stock versions (except perhaps the 60's/early 70s factory headers, which were pretty damn good).

Mark's header is the only one that I have not needed a dyno to feel the difference in performance. You can feel the torque and acceleration improvements in the seat of your pants, big time, and see the additional 4-500 rpms at the top, where it is not just making noise, but still making HP. I once had a passenger with me who described third gear in the coupe as "relentless". On the last dyno run of the coupe's new engine (now back out of the car for more work), and before it was properly dialed in, it made over 144 lbs of torque fairly well down on the rpm curve. I don't have the chart with me to give you the exact figures and rpm point, but it really did surprise everyone given the cam profiles, etc, of this particular engine.

And they have continued to improve the quality and manufacturing processes. Well worth saving the extra bucks to maximize the benefit from all the other mods you have done to make the engine breath deeper.

BTW, I think I am going to just sell the chromed header I took off the coupe's 1800. This is the VAS version.