DIY 3-Inch Dual Exhaust Install - Shout At The Devil

Hooker Headers’ Slip-Fit 3-inch stainless dual exhaust system can be installed at home without using a welder.

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There comes a point in just about every build when you will need to relinquish the reins and enlist the talent of another person. Usually, these points are engine machining, paint, interior, and exhaust. Because these tasks take either specialty tools or skills to accomplish, it’s pretty easy to understand why so many seek help. This issue is sort of a thing of the past when speaking about exhaust. Thanks to Hooker Headers, a division of Holley Performance, we were able to install a complete, 3-inch, mandrel-bent stainless system under a ’70 Camaro without touching a welder or using anything more than typical handtools.

The system we are talking about is Hooker’s new ’70-’81 GM F-Body exhaust system (PN 42502HKR). It was developed for direct fitment to Hooker’s LS swap headers, but we’ve come to find out it will fit most long-tube headers as well. We were able to hook it to a set of headers that, quite frankly, look like they were built in the late ’70s.

The system is offered in two diameters, 21/2 and 3 inches, and includes high-quality band clamps and EO-style hangers. The tubes are stainless and are bent with a mandrel instead of a muffler shop-style compression bender. Compression-bent systems typically feature severe restrictions that, in turn, rob significant horsepower from your engine. The Hooker system comes with a set of TIG-welded 304 stainless steel absorption mufflers that feature composite stainless steel and high-temp E-glass packing in a straight-through design.

Another killer feature is the high-efficiency stamped x-shaped crossover that will equalize the system, increase torque, and smooth out the exhaust note. The fitment was spot on, with no clearance issues to report, and the OE quality hangers will keep the system in place but isolated from the body.

By the end of the day, we had a beefy-looking set of tubes tucked up nicely under the car. Once fired, the motor has a mellow tone down at idle, but you still hear the cam thumping away. Once you get into the throttle and she hits three grand, the tailpipes come alive and words like cackle, snappy, and crisp all come to mind.

1970 Camaro Exhaust Install Parts 2/23

1. Here is the system we received from Hooker Headers. We decided to use the 3-inch system for our 433hp small-block, but a 21⁄2-inch system is also available. Each system is supplied with a stamped crossover and high-flow TIG-welded 304 stainless steel absorption mufflers. OE-quality hardware (clamps, hanger rods, and rubber isolators) is provided to ensure excellent fitment and a leak-free installation. The layout of the pipes provides compatibility with stock parking brake cables and Ridetech/Fatman Fabrications four-link suspensions (according to Hooker, this is an industry exclusive feature in an off-the-shelf package).

1970 Camaro Exhaust Install Clamp 3/23

2. One key factor to the slip-fit system is these high-quality clamps. The clamp clenches down on the outside tubing and creates a solid, leak-free connection.

1970 Camaro Exhaust Install X Crossover Pipe 4/23

3. Another feature is the crossover or X-type pipe, offered in both 21⁄2- and 3-inch configurations. These equalize exhaust pressure and enhance performance.

1970 Camaro Exhaust Install Rusty 5/23

4. Here is the super-simple and rusty system that was under our Camaro. It’s a pretty common layout for something of this era, with two crappy mufflers and turndowns right before the rear end. This made the car fairly loud and stirred up a ton of dirt. A loud car does not offend us, but this loudness was more in the car than out of it. The drone in the interior was so bad, you felt like you needed to pop your ears.

1970 Camaro Exhaust Install Muffler 6/23

5. Here is a closer look at the mufflers. This should give you a good idea why this car needed a new system. We are not fans of exhaust leaks, and the huge rust holes in the mufflers made for some pretty strange sounds.

1970 Camaro Exhaust Install Comparison 7/23

6. Because our system is so simple, all we needed to do to get it out was undo the collector hardware and two hangers at the back. We slipped the new Hooker 3-inch system together to give you a clear side-by-side comparison—and let’s face it, there is no real comparison. The only thing the old stuff might have had going for it was the cost, which had to be next to nothing.

1970 Camaro Exhaust Install Tailpipes 8/23

7. Hooker’s instructions have you start at the front and work your way back. Since we are retaining our old headers, we are going to start at the tailpipes and work forward. This will allow us to determine what, if anything, we might need to join the new exhaust to the old headers. We used a few heavy zip ties to hold things in place like the tailpipe and over the axle tubes seen here.

1970 Camaro Exhaust Install Mounting Bracket 9/23

8. With the 3-inch pipes, you may encounter some clearance issues with the rear brake line. All we had to do to remedy this issue was move the mounting bracket over a bit and drill a new mounting hole. You can see we also have an old Holley blue fuel pump mounted in the exhaust area that we relocated, but that is only an issue we have. In a stock car, this would not be here. We are going to re-plumb the fuel lines in the car, and the pump will get a new location out of the way.

1970 Camaro Exhaust Install Tighten Clamps 10/23

9. As items get slipped together, the clamps are tightened just enough to keep things from falling apart—but not so tight that we can’t adjust the joints.

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