Steve Baur
Former Editor, Modified Mustangs & Fords
January 24, 2007
Contributers: George Trosley

In the April 2003 issue of MM&FF we covered the installation of ProCharger's P1-SC supercharger on our resident '90 Mustang GT. As far as project cars go, we haven't bothered to give this one a name yet, but we've continued to modify it with a Cobra R four-wheel disc brake upgrade from Ford Racing. With 330 hp at the wheels of the little mare, we definitely had to do something about the stopping situation and the FRPP kit worked like a charm.

This time around we've decided to chuck the stock shorty headers in exchange for some long-tubes, but we didn't stop there. We also needed to get the pony in compliance with the state of New Jersey's emissions requirements and we accomplished that with a set of high-flow catalytic converters. Lastly, the venerable Flowmaster mufflers and stock cat-back pipes were traded for a true 2.5-inch cat-back system.

Choosing an aftermarket exhaust can improve both the sound and performance of your pony, and with what we hope to do with it in the future, we looked for an exhaust upgrade that wouldn't be a restriction later on.

When it comes to exhaust tones, just about every manufacturer has its own unique signature. The best way to choose one that you like is to go to your local cruise-in or better yet, visit a Fun Ford Weekend or NMRA event. Listen to the cars as they do their burnouts. Listen to them go down the track and then head to the pits. Find the cars that sound good to you and then find out what they're running. Granted you might like the sound of a big-block Pro car, but running open headers on the street really isn't an option, not to mention that 4-inch collectors and 2-inch primaries probably aren't the best setup for your bolt-on street car.

Our pony's combination is somewhat unusual at this point. It's a stock five-liter from intake to pan, but we're cramming 10 psi of boost through it with some help from ATI. Someday, we would like to get some nice cylinder heads and a hotter camshaft, but for now she's mostly stock. We do have an intake manifold on the way and with all of these parts, we're expecting a power output in the neighborhood of 400-450 at the rear wheels. With those plans in mind we decided to go with long-tube headers and a full 2.5-inch exhaust system.

The long-tube headers we selected are from Bassani (PN 5092R), are chrome plated and retail for $731.50. These optimum-length, 14-gauge carbon steel tubes are mandrel bent and step up in size from a 1 5/8-inch diameter to 1 3/4 inches. This stepped design keeps exhaust from reverting back up the tube and the smaller sized tube off the head maintains torque, while the larger tube downstream aids horsepower. The individual tubes slip-fit into Bassani's exclusive "Extractor Collector," which induces a scavenging effect, further improving performance. The headers come with instructions and all necessary parts for the installation from bolts to gaskets and even antiseize.

Bassani has a new line of exhaust components called BX, which replaces Bassani's standard, stainless steel tubing with mild steel construction wherever possible to reduce the cost and price of the part. We used a BX shorty X-pipe (PN 50933R) equipped with high-flow catalytic converters. With New Jersey vehicle inspections being the brutal tests that they are, we averted potential problems by going with the proper cats. The BX X-pipes are mandrel bent and made from aluminized steel for corrosion protection. Our '90 GT was already running an off-road X-pipe, and we happen to like the change in tone that occurs when using one, so that is why we chose the BX unit.

In order to maximize future gains in horsepower, the stock 2.25-inch cat-back system had to go. The kinks and bends that aid in installation on the assembly line simply have no performance in mind. To remedy this, we opted for the BX AFT-CAT exhaust system.

The Quiet Thunder kit features aluminized mandrel-bent 2.5-inch tubing and Bassani's "Composite" construction mufflers. The mufflers feature durable Stainless Steel internal construction housed in a 16- gauge aluminized steel case. For 1987-93 Mustang GTs, order PN 5093GT5, which sells for $531.25.

On the passenger side, remove the mass air elbow and if you still have them, the emission lines that run to the air pump. This will give you more room to work and you'll need it.

Since Bassani includes all of the clamps and bolts needed, installation is a snap. Ball and socket connections eliminate the need for welding and also offer excellent sealing characteristics. The step headers come as separate tubes, but instructions are included and tell you which order to install them in. Once you have them loosely hung, you can slip on the collectors and then the ball and socket flanges that connect them to the X-pipe.

The X-pipe features the proper factory hangers, as does the cat-back system. This makes installation for these parts a simple disassemble/reassemble deal. The tailpipes offer plenty of clearance around objects like the gas tank and upper control arms. Which keeps things rattle-free.

In the instructions for the headers, it mentions that some modifications may be necessary, but we found no issues that needed correcting as far as the headers were concerned. The long-tubes do relocate the O2 sensors farther back and, for this, Bassani recommends pulling the wires out of the harness to gain the needed length. We needed to re-route the "low oil" level sensor, which runs with the O2 sensor in the same harness. This seemed rather tedious, as re-routing the harnesses required quite a bit of Zip Ties to keep them out of the way of the headers. Get yourself some O2 extensions and be done with it.

The Bassani headers and BX exhaust system sounds great and fit well. We had hoped to bring you some updated track and dyno results, but the stock replacement clutch that was installed a few years back isn't really happy with the 300-plus rear-wheel horsepower and said "Uncle" more than once when shifting into fourth gear at the strip. Therefore be sure to check out our next installment of our Procharged pony for the details.

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