Frank H. Cicerale
August 24, 2007
As you can see, the Stainless Works muffler (left) is much smaller than the factory Ford muffler (right). While the outward appearance is nothing to get your shorts in a knot over, the main difference between the two mufflers is their internal construction.

Stainless Works has gone one step further with its systems, however. The after-cat system we installed on Project MILF is CNC-bent. Bending a tube in this manner is done entirely by a computer that controls both the position of the tube and the rotation of one bend in relation to another. Instead of having a person take care of bending the pipe, the machine cuts the tube to the desired length and then bends it perfectly. In addition, by CNC-bending the tubes, you can get away with using stainless tubing with a thinner wall for weight savings. Naturally, the stainless pipes have great corrosion resistance.

Additionally, our Stainless Works system came complete with an x pipe crossover. Obviously, the name for each component is a derivative of its shape; for example, an H-pipe looks like the letter "H," while an x pipe is manufactured in the shape of the letter "X."

A difference lies between the power and sound. An H-pipe has a deeper tone, one more in line with a classic musclecar, while the x pipe has a higher pitch. Both can make great power, but we've generally seen x-style pipes outperform the H-style exhausts.

Finally, we were forced to choose between long-tube and short-tube headers. Shorty headers are usually the closest thing you can get to a direct replacement for the factory exhaust manifolds. In addition, they are fairly easy to install. By comparison, long-tube headers dictate a more involved install, and there can be some clearance issues, depending on the vehicle in which they are installed. As for which is better, the long-tube or the short-tube, you will get varying opinions. The general consensus is that short-tube headers will improve low-end torque on lower-horsepower applications, but they give up some horsepower upstairs. We went with the long-tubes.

With The stock exhaust tubing off, it was fairly easy for Winter to remove three of the four O2 sensors. Two were in the tubing following the cats, while the other was in the passenger-side head pipe. The final O2 sensor was located in the driver-side exhaust manifold. More on that debacle later.

With that said, we got the car up on the lift at Crazy Horse Racing, and in a little over a day's time, Chris Winter swapped out the factory exhaust pipe, cats, mufflers, and exhaust manifolds for the Stainless Works long-tube headers, high-flow cats and mufflers, and stainless steel pipes. One thing we noticed was that the installation of the headers is something you might want to perform with the car on a lift. It was rather involved, as we had to unbolt the steering rack, remove the dipstick, loosen the motor mounts, and raise the engine to give us enough room to slide in the headers. Also, we had to switch a few of the factory studs and bolts for regular Grade-8 bolts to avoid contact issues with the header tubes. The Stainless Works kit does not come with bolts, so you can either reuse the factory bolts or order aftermarket ones.

When we were done, we went back to the dyno. The results were interesting. The Three-Valve picked up slightly when it came to peak power, but it improved by as much as 20 rwhp and 25 rwtq at some points in the curve (see sidebar). And, keep in mind-this came with no additional tuning. If we could do it over again, we'd consider installing 1 5/8-inch primary tubes, as they would probably help MILF's engine make more power, especially in the midrange. Project MILF was also noticeably louder, though not obnoxiously so.