Flowmaster U-Fit Dual Kit - Making It Fit - Tech

All in all buildin' a hot rod at home is a great experience-it may not be all fun and games, but there's nothing like transforming a junker or a big pile of parts into a cool hot rod on your own.

Either way they're a ton of fun, but building a hot rod car or truck in your home shop or garage versus buying one already finished is by far the way to go, in my humble opinion anyway. That said, there are a few processes involved in sewing one together that are more often than not farmed out to professionals, or, at the very least, require outside help of one sort or another. The most prevalent of these are electrical wiring, bodywork, paint, upholstery, and often exhaust systems. Over the years I've performed most of these chores at home (sometimes more successfully than others) as (like a lot of us) I'm always working on a shoestring budget and don't have the cash needed to hand those jobs off to somebody else to do for me. Here we're going to take a look at a great product that gives us low-buck builders an affordable option to a custom-fabricated exhaust system: Flowmaster's U-Fit dual kit.

Rather than actually doing the install myself, I'd heard that one of my pals was having a Flowmaster's kit installed in his Chevy by a mutual friend whose shop is right down the street from our offices (a perfect excuse to get out of the office for a little while and shoot a few snapshots). And though, in this case, the job was done in a professional shop rather than at home, take a look at what we think is a great and affordable alternative to trailering your hot rod to a muffler shop and paying for a custom-bent exhaust system.

Flowmaster's U-Fit dual exhaust...        read full caption Flowmaster's U-Fit dual exhaust kits come complete with all the pipes needed to fabricate a custom dual exhaust system for nearly any vehicle. They're available in 2.25-, 2.50-, and 3.00-inch pipe diameters, and include front adapter pipes, intermediate pipes, an H-pipe assembly, and over-the-axle pipes. The pipes are designed with slip-fit connections for easy assembly using muffler clamps, or slip-fit and welded together by those with the correct equipment.	The pipes are mandrel-bent,...        read full caption The pipes are mandrel-bent, 16-gauge aluminized steel tubing for long life, too. Just keep in mind though that the U-Fit kits consist of the tubing only. Mufflers, hangers, and clamps will have to be purchased separately.	This is a copy of the diagram...        read full caption This is a copy of the diagram that comes with the U-Fit kits. I've found that laying the components down on the driveway or garage floor is a good way to visualize possible layouts for your application (just don't forget to allow space for the mufflers when you do so).
Once you've got your old system...        read full caption Once you've got your old system stripped and out of the way (or you've installed manifolds or headers on a project without any system at all) and you have a good idea of how you want to lay out your system, you can roll up your sleeves and get to work. Josh (the Muffler Man) began by bolting up the header flanges to the headers.	Once the collectors are bolted...        read full caption Once the collectors are bolted up, the next step is to locate your crossover, or X-pipe. You'll want to make sure you mock it up as high as you can because these first steps are going to determine how low the system is going to hang. In this case, the job's a bit easier because Josh is working under a lift rather than laying on his back in the driveway-but, if you're on the floor you can block this piece up with a few scraps of 2x4 or whatever's handy. This may be a good time to mention that you'll be doing a fair amount of trimming on the various pieces of pipe as you go.	With the collectors attached...        read full caption With the collectors attached and the crossover pipe mocked into place, it's then time to make the connection between them. Grabbing the next pieces of tubing (from those that you laid out on the floor you can then hold them up between the collector in the front of the crossover, make your marks on the tubes, and trim them to fit). If you're going with the slip-fit and clamps route make sure you make your marks and cuts at the ends of the tubing that aren't expanded. Also remember that each slip-fit connection can be rotated to allow for a wide variety of paths for the system. If you're welding it together, go ahead and mark and cut the tubing where appropriate.
Once you've made your connection...        read full caption Once you've made your connection from the headers to the X-pipe, take a look and make sure it's located low enough so it doesn't contact your driveshaft yet high enough so it won't be kissing the ground when you hit a good-sized bump. If you're satisfied you can then clamp or tack weld them and move onto the next step.	Next are the two extension...        read full caption Next are the two extension tubes that run from the rear of the X-pipe to the muffler inlets. These (as do most of the components of the kit) have expanded ends that'll slide over the rearward ends of the X-pipe. They also have a bend that'll get everything running parallel to the framerails again. Cut these two pipes to the appropriate length and slid them on to the X-pipe and rotate them so the next components will be level with what you've got together so far.	The next step is to hang your...        read full caption The next step is to hang your mufflers. Each car or truck will be different in regard to the space you'll have for the mufflers so the call on their placement is gonna be up to you. In this case John's Chevy had a large expanse of space on either side of the driveshaft so about a foot or so of transition pipe was run rearward from the X-pipe to where the mufflers will attach.