Michael Johnson
Technical Editor
April 1, 2000

Step By Step

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The DynoMax ceramic-coated headers looked great and installed easily, except for a couple of minor snags.
We gave Parkway Ford a call for a MAC after-cat system featuring Flowpath mufflers. Parkway carries a plethora of Mustang performance parts in its Performance Center.
The first thing to do when removing the headers is to loosen them from the H-pipe. Start by taking out the O2 sensors. They’re attached to the H-pipe just below the header-mounting flange. Use a 7/8-inch open-ended wrench to loosen it. Once the sensors are out you can loosen the H-pipe-to-header mounting bolts.
Now you can remove the header bolts and discard the factory headers. Our new DynoMax headers will look and perform much better than the stock pieces.
Carefully ease the new headers into position. Notice we have put the plug wires to the side to make it easier to install the new headers. The dipstick tube has been removed, and the mounting ear will need to be modified to fit the new headers.
With the ROL header gaskets we’re using, we just threaded in the two outside header bolts and slid the gasket into place.
Thread in the header bolts for the new headers and gradually tighten them all down. We ran into a couple of problems when mounting the headers. For one, the production process left residual material in a couple of the mounting holes, necessitating the use of a drill to clean them out. Another problem we encountered was the header tube for the No. 7 cylinder restricted us from installing the backside bolt. We had to open up the hole ever so slightly, then use a hammer to punch the bolt through. These minor problems are not uncommon with any header manufacturer, and they didn’t detract from the overall quality of the DynoMax headers.
Once the headers were installed, we devoted our attention to mounting the H-pipe. First we loosened the downstream air tube. When we removed the factory headers, we also removed the air tube’s mounting point in the engine compartment. This circular clamp holds the tube to the H-pipe. Loosen the clamp enough to where you can dislodge the tube from the H-pipe.
Loosen the H-pipe from the flow tubes and remove the H-pipe. It’s a good idea to apply lubricant to the H-pipe’s top two rubber mounts above the transmission. This will make it a lot easier to remove the H-pipe.
It took two people to install our Redem/ Tri-D Industries H-pipe. Notice we have already installed the flow tubes and mufflers from our MAC after-cat system. The easiest way to get an H-pipe into place is to get the rear-most part of it up above the flow tubes and slide the two mounting ears into place—all the while making sure the H-pipe mounting flanges meet up properly with the headers.
The MAC after-cat is one of the easiest systems we’ve ever installed. While the system’s adjustability is limited, it is one of the few, true, driveway bolt-ons out there. The flow tubes/mufflers slide over the rear axle to be attached to the tailpipes, which use the factory hanger at the rear.
Loosely attach the flow tubes to the H-pipe and check for clearance around the control arms and along the framerails. Our MAC after-cat features 21/2-inch-diameter pipes front to back.
The passenger side was another story. We would never have guessed we would ever be able to get an after-cat system on this car, much less a 21/2-inch system. We were pleasantly surprised to find that the MAC system wasn’t that difficult.
This is the part of the Panhard mount needing a little extra clearance. We used a cut-off wheel to clearance the mount, making sure to leave enough of the mount intact to retain its integrity.
The tailpipes attach at the rear using the factory rubber hangers. We wish the mounting arms were a little longer because the tailpipes rub up against our bumper cover—something we will need to take care of before the pipes and cover become damaged.
On Dynamo Motorsports’ Dynojet, our new exhaust system gave our stock 5.0 a boost of 2 hp, but a loss of 1 lb-ft of torque. However, even though peak gains were not siginificant, our horsepower and torque numbers didn’t fall off rapidly at the top end, showing us that the free-flowing exhaust system is doing its job. Also, keep in mind that for our baseline numbers the car did have Flowmaster two-chambers dumping in front of the rear axle—so to have any gain at all is promising.

When you think of easy horsepower bolt-ons, K&N air filters and underdrive pulleys are near the top of the list, but nothing gives you the horsepower boost and the aural pleasure of a performance-exhaust system. Furthermore, the addition of a performance exhaust is the best way to prepare your Mustang for further modifications. The horsepower possibilities a performance exhaust affords are unmatched by any other modification, which is why we’re stepping up to an aftermarket system on our ’93 coupe.

To future-proof the little black coupe, we gathered new components from DynoMax, Tri-D, and MAC. We went against the single-company theme for a variety of reasons. We were mostly looking for components that looked good and those that would clear our Kenny Brown TracKit Plus suspension out back. What we ended up with were DynoMax ceramic-coated headers, a 2-½-inch step-up turbo, an H-pipe with cats from Redem/Tri-D left over from our H-pipe vs. X-pipe article (“Pipe Dreams,” Nov. ’99, page 80), and a 2-½-inch MAC after-cat system received from Parkway Ford.

The good folks at Parkway were happy to help us out with our exhaust needs, and they got the after-cat system to us at our Lakeland, Florida, offices within two days. We chose the DynoMax headers because of their anvil-solid construction and beautiful ceramic coating. And we liked the chrome tailpipes of MAC’s after-cat—not to mention the easy installations we’ve previously experienced with both of these parts.

Another reason we chose the MAC after-cat system was because we just installed a Kenny Brown TracKit Plus Panhard bar kit, among other KB suspension components. The TracKit Plus is available for stock and DynoMax exhaust, or Flowmaster and MAC after-cat systems. Our coupe had the TracKit Plus for use with Flowmaster or MAC systems. We still had to modify the mounting arm for the TracKit Plus, but the integrity of the arm was left intact. We also can’t wait to install Kenny Brown’s upper and lower control arms because doing so should give us more room to tweak the after-cat system to the most desired point.

We’re not sure why, but even with our exhaust upgrade the car is still too quiet for our tastes. We don’t know if it’s because of the MAC after-cat system; we’ve only heard one in off-road pipe form. The H-pipe we know to produce good sound. We’re not going to an off-road pipe because of emissions restrictions, so we may need to try different H-pipes to see how we can attain a powerful sound while still retaining emissions legality.