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.

1970 Camaro Exhaust Install Flanges 11/23

10. Once we had the entire system together, we found it was long enough to mate to our existing headers. We have a couple of options here: cut off our old flanges and weld them to the new stuff, purchase new flanges from Hooker, or try to make our old headers a slip-fit style. After a simple measurement of the collector, we decided on option three—cut off the flanges for a slip fit.

1970 Camaro Exhaust Install Saw Flanges 12/23

11. A combination of cutoff wheel and reciprocating saw was used to lop off the flanges.

1970 Camaro Exhaust Install Deburred 13/23

12. The cuts were deburred, and the new pipe slipped in place.

1970 Camaro Exhaust Install Slip Fit 14/23

13. If you have never experienced a slip-fit system, then here is a close-up of the joint. Hooker expands one pipe just enough and makes four relief cuts so it will slip over the joining pipe and allow the clamps to easily tighten it up. This photo illustrates the pipes together, but not enough.

1970 Camaro Exhaust Install Push Together Pipes 15/23

14. The pipes must be pushed together enough so all you can see through the relief cuts is the pipe below. If you can still see the end of the lower pipe, you will have an exhaust leak—so make sure they are pushed together enough before tightening the clamps.

1970 Camaro Exhaust Install Insulators 16/23

15. Hanging exhaust systems safely requires quality hangers and isolators. Hooker’s new two-hole rubber insulators work perfectly with Hooker’s new hanger rods and reduce the transmission of exhaust vibrations. There are four hangers in the system, two that go right above the axle as shown here, and two that go after the axle. We decided to use large, self-tapping screws to mount the hangers.

1970 Camaro Exhaust Install Rear Hangers 17/23

16. The rear hangers are configured a bit differently, but still feature the same heavy-duty rubber isolators. These must be assembled as shown…

1970 Camaro Exhaust Install Floor 18/23

17. …before being mounted to the trunk floor right at the trunk drop-out panel seam.

1970 Camaro Exhaust Install Adjusting 19/23

18. Now that we had all the pipes and hangers in place, it was time to start adjusting everything and locking down the clamps. We started at the cross-pipe and worked our way back. We found the best alignment of the mufflers was parallel with the floor.

1970 Camaro Exhaust Install Leaf Springs 20/23

19. With the front aligned and locked down, we got the tailpipes centered between the quarter and the leaf springs…

1970 Camaro Exhaust Install Tighten Clamps 21/23

20. …and then tightened up the last set of clamps.

1970 Camaro Exhaust Install Front View 22/23

21. Here is an overall view of the system from the front. As you can see, Hooker did a spot-on job of getting the pipes perfect for the second-gen Camaro floor.

1970 Camaro Exhaust Install Rear View 23/23

22. Here is a rear view of the system. We are pretty impressed with the entire thing, from the single-day, no-welder install to the added ground clearance. We were a bit skeptical that the 3-inch pipes would fit this well, and with no floor modifications, and we are happy to be wrong. The car sounds sweet with the deep thumping idle and a raspy cackle at high R’s, and thanks to the all-stainless construction, it should stay nice for a very long time.

Sources

Hooker Headers
Aberdeen, MS 39730
662-369-6153
http://www.hookerheaders.com
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