In Stock Car racing, every last fraction of a horsepower matters-and that's why you see an X-pipe from Dr. Gas on every single Cup car in NASCAR. Although the exact science of why they work isn't fully understood, we do know this much: When any given exhaust pulse arrives at the "X" juncture, the pulse expands along both available paths. In doing so, a negative pressure wave travels back to the exhaust port, which aides in exhaust scavenging. Balance pipes, sometimes called "H" pipes, function similarly, however, the effect is diminished due to the balance pipe's smaller diameter and the added bends the gas flow is subject to.
Before Lang could start on...
Before Lang could start on the Dr. Gas exhaust system, we needed a custom double-hump trans crossmember. Our old crossmember was a single-hump bar for a Turbo 350, and we now had a 700-R4 with duals. Here, Lang Paciulli, of LP Racing, has cut a 6-foot length of 1.25-inch diameter, 0.083-wall chromoly pipe, and is making some bends.
After thinking long and hard about the exhaust options for our '75 Chevy Laguna (Project Talladega), we decided that a no-holds-barred NASCAR-style exhaust was what we wanted. We liked the idea of maximizing our power just like the big-name racers, and the look would be a perfect fit for our NASCAR-themed project. Moreover, with a solid-roller 408ci small-block lurking underhood, we figured the sound alone would strike fear in the sport compact crowd, and it has so far turned out to be a great deterrent with no takers yet.
When we called Dr. Gas to sell them on the idea, we were pleasantly surprised to find out they had been following Project Talladega since the start. They were waiting for our call, and had a recommendation for our Laguna already picked out. Just to be clear, there is no "bolt-on" side-exit exhaust kit from Dr. Gas. You buy components that you will have to fabricate into a unique system. When you receive your shipment of Dr. Gas components, you will have the option of building the system yourself, or bringing it to a shop. In either case, the cosmetic result you get will depend on the work you put into building it.
Lang is sizing up the crossmember...
Lang is sizing up the crossmember so that it aligns with the existing frame bolt holes while providing necessary clearance for the dual exhaust. This is an iterative process where the crossmember was bent repeatedly to arrive at the ideal shape. As a chassis builder, this is one of Lang's sharpest skills.
Straight from Dr. Gas's "NASCAR" parts bin, we received a universal 3-inch X-pipe made from oval tubing (part No. U3O, $399.95). The Dr. Gas folks matched this to a pair of 3-inch Street Rod Boom Tube mufflers (part No. BTM3, $550.90). Looking more like flat, side-exit exhaust tips than mufflers, the Boom Tubes are essentially open, with spin traps welded inside them to mitigate some of the sound. They are loud, so be forewarned that you may run afoul of the local gendarmes if they don't fancy your automotive style. As fate would have it, we drove our finished Dr. Gas exhaust on the Riverside, California, freeway during a Harley rally, and suddenly found ourselves cruising in the midst of 15,000 wild hogs. We got a big thumbs-up from all for two reasons: our satin black paint fit right in with the biker vibe, and because we were still the loudest thing on the highway. The scene could easily have been an outtake from a Mad Max movie.
Building an exhaust system like this requires special fabrication skills, and for that we turned to LP Racing of Upland, California. The "LP" in LP Racing is Lang Paciulli, who specializes in race car fabrication and TIG welding in particular. Lots of shops do welding, but it's MIG for the most part. For those shops, welding is an unpleasant necessity, but Lang's interest in TIG welding borders on compulsive. If two metal objects need joining, chances are Lang will TIG weld them-with a smile on his face. As a result, it's no surprise that he's good at it. Lang's TIG skills are known throughout southern California, and like many others, we sought him out for our Dr. Gas project.
 After cutting the crossmember...  After cutting the crossmember to the proper length, Lang cut a flat section where it would mate with the frame. |  We're skipping a few steps...  We're skipping a few steps here, but the summary is that Lang is TIG welding a flat tab on the crossmember where it meets the frame. This tab has been shaped to fit the tube, and has a nut welded to the inside so that a bolt can be threaded into it from under the car. The placement of the tab and the nut has been precisely located with direct measurement from the Laguna's frame. |  A chassis builder by trade,...  A chassis builder by trade, Lang has a multitude of generic brackets and gussets lying around his shop. He found one in particular that with only slight modification worked well as a trans mount. Here, Lang is checking the fit, then he'll tack weld it in place. |