Part One: The Teardown
Now that you know about the parts, let us give you some advice on tear-down and installation. JBA supplies great directions with its products, so the following information is just a highlight of some key points. You won't need a lift to do this job because the headers load from the top. But, you will be under the truck a lot, so a lift would be nice-a jack and jackstands will be sufficient. Before you grab a tool from the toolbox, grab some penetrating fluid like WD-40 and spray all the fasteners and hangers.
1. To get the factory exhaust manifolds out, you will need to remove the six 13mm bolts from the flange and three 15mm bolts from the collector. Before you grab the sockets, carefully remove all of the spark plug wires by grabbing the boot and pulling it off of the terminal. Whatever you do, fight the urge to pull on the wire itself; only bad things can happen if you do it that way. | 
2. To get the tailpipe assembly out, you will need to remove the two 15mm bolts from the flange and cut the pipe right behind the muffler. The assembly is too long to remove together without tearing half the rear suspension apart, so this simple cut will save you an enormous amount of time. | 
3. The rubber hangers do a great job in holding the exhaust system in place, but that also means they are a little difficult to remove. However, because you oiled them earlier, a large set of pliers or a prybar should do the trick. |
Side-By-Side
Once the stock system was removed from the Yukon, we laid it out next to the new JBA system. Here's how they matched up:
1. Here is a comparison shot of the manifold and the JBA header. As you can see, the headers give the exhaust gases a smoother path to travel before they commingle in the collector. This improves flow and, in turn, improves power. Also, take note that the headers take up just a little more room than the manifolds, so there will be no clearance issues to speak of. | 
2. The tailpipe and muffler assembly from JBA is not only constructed entirely out of stainless steel, but it also features the company's straight-through muffler for lower backpressure and increased flow. You will also notice the absence of the rear muffler that the factory uses. JBA spent a lot of time in the R&D department to keep the exhaust note quiet yet still make power without the use of one more restrictive muffler. | |
Part Two: The Install
Now for the installation of the new parts. As stated earlier in the story, both the left and right header feed in from the top. Be careful when you are sliding these into place, because one wrong move will break off a spark plug. You could remove them just to be safe, but as long as you are careful there is no need.
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1. The driver-side header features a flat collector flange that JBA provides a gasket for in the kit. The passenger-side has a ball/socket-style collector that needs no gasket, but JBA recommends a small amount of high-temp silicon be used to provide a perfect seal. | 
2. Because there is still a piece of the factory exhaust system in place, the converter assemblies and the intermediate pipe bolt right to it. The only adjusting you will need to be aware of is for the muffler and tailpipe. Install all of the pieces and just snug up the clamps. |