I’m old enough to remember back when every auto parts store had a big barrel full of Cherry Bomb glasspacks sitting up by the registers, like the world’s biggest impulse buy. Today, the merchandising is slightly more sophisticated, but the mufflers and the sound are still the same. Since I’m always looking for ways to screw up my perfectly good 2004 Mustang V6 coupe, I’ve had an itch to throw a glasspack on in place of the 2-into-1 stock exhaust. I had no idea whether it would work any better, or even whether or not it would sound like ass. But it seemed like an easy project, and the parts were cheap, so I dove in. Here’s how it went:

The stock exhaust on the V6 is, as mentioned before, a 2-into-1 Y-pipe that feeds about eight feet of crush-bent 2.25 inch pipe and a regular muffler mounted ahead of the rear axle. There are a bunch of different 2-into-1-into-2 bolt-on exhausts for this car, as well as true H- and X-pipe dual setups, but they’re all fairly expensive for what you’re getting - anyone who expects more than 2 or 3 horsepower out of an exhaust is delusional. On top of that, duals are inevitably heavier than the stock exhaust, and light weight is about the only thing the V6 Mustang has going for it over it’s GT brother.

Cherry Bomb glasspacks are cheap. I picked up PN 87516 (2.5 inch inlet/outlet, 29.5 inches overall length) at Pep Boys for $30 even, while a 2.5 inch turndown cost me $7 at NAPA. The most expensive part was actually the “starter tube” that bolts to the stock ball fitting, at $38 for a pair from JBA, though I still have one left to sell. We’ll call the total cost $56.

The starter tube went into one end of the glasspack with a little gentle persuasion, and after cutting off the flared 3-inch long section of the turndown with a Sawzall, it slid right into the other. The total overall length from end to end turned out right where I wanted it at 38 inches.

As a welder, I am an awesome writer. Nevertheless, look at that penetration! The starter tube and turndown got joined permanently (with any luck) to the body of the Cherry Bomb. Note: the powder coating on this muffler was no match for brake cleaner - good to know when prepping it for welding.

Now, we separate the men from the boys - to get the stock exhaust off without dropping the rear axle, you have to cut it at some point. I picked a spot where I’d have good access with the Sawzall, and more importantly, I would be able to reconnect the pipe with a band clamp should I end up absolutely hating the way the glasspack sounded.

Once you’ve made the commitment and cut the pipe, the stock exhaust comes out easily. Rather than fighting the rubber hangers, I simply unbolted both of their metal brackets from the car instead. The forward bracket that supported the muffler was then removed and put back on the car, since I planned on using it to hang the new glasspack.

To mate the Cherry Bomb up with the rubber hanger, I bent up some steel rod I had laying around. Hooray, Chinese flux-core welder! It looks ugly, but it’s functional.

Once again, here’s the finished product. It’s short enough to completely clear the rear axle with room to spare, and hangs nicely from the stock bracket and donut. With everything bolted up, I crossed my fingers and turned the key. Much to my relief, it sounds great - lots of nice musclecar bass, and it actually gets smoother and quieter at WOT as the revs climb. I won’t say it sounds like a GT, but it’s no fart can, either, and I’m very happy with how it came out. Especially when you consider the cost, and how little effort it took to do.

Here’s a short video of how the new exhaust sounds:

Update 3/12/09:

One more video, from outside the car…