DanMan_S

Yeah, any of the times I've dealt with a exhaust shop and the pipe was a 'screaming deal', it was aluminized pipe. In our climate, that stuff will rust ASAP.

Even for other vehicles, the long tube header kits are the same. On my Z06's, my Mustang, my SRT8 jeep, my various GM and Dodge trucks, the bolt in kit with the long tubes, y pipe (x pipe in the case of cars with dual exhaust), cats/no cats are pretty much the same. With the except of custom jobs, say engine swap cars, old mopars, modern long tube kits are pretty straight forward bolt in jobs. On a few of my vehicles, I'd just run the headers with the factory catbacks, I know that my Mustang was already loud enough with the factory mufflers, headers, xpipe and no cats. In the case of my GM trucks, the factory exhaust really drones with headers, which is why I'd swap to the corsa catbacks. Based on my experiences, going with the longtubes can be a easier install than shorties. Why? Because the exhaust manifold flange is tucked in so closely between the engine block and the frame rails that it's nearly impossible to undo the bolts, especially if the truck has some mileage and lots of heating/cooling cycles. That's why I end up cutting the down pipe instead, as it's faster to simply take the sawzall to the down pipes than try to get those bolts undone. Heck, I've broken those downpipes flange studs a few times, at which point the whole down-pipe has to come out no matter what to get the remains of the stud out. Dealing with the new downpipes and cats is easy as a lot of the header kits are really well done and easy to assemble. The fit and finish of the American Racing kits is always great, and you can loose fit the downpipes to the headers and the catback, nicely tighten the headers to the engine, then go back and quickly tighten up the rest of the flange connections under the vehicle.

Most systems for these trucks that are readily available will be exactly like I posted. If a guy wants to get crazy and put headers with primaries that are longer than that, he can pretty much do whatever he wants and get a custom made set, but for most of us, we're buying commercial kits that are a direct bolt in swap for the factory system. But along those lines, how is replacing the manifolds with shorty headers not considered modding? Modding is simply replacing factory parts with aftermarket pieces. Shorties, long tubes, or a full cat back are all modding the exhaust. It doesn't matter if it's a simple bolt in kit, or a full, custom mandrel bent and welded kit. A mod is a mod.

The long tubes replace everything that is bolted up on the factory truck. If you look under the truck, the factory exhaust is bolted at the manifolds, and after the cats where it meets the cat back. The long tubes are a direct swap for everything up to the cat back flange and require NO MODIFICATIONS. It is definitely a simple exhaust modification as all of those parts are included with the long tubes. So a long tube kit will include the headers, the new down pipes, the new Y pipe and the catalytic converters (or straight pipe if you want to skip the cats). The cutting I do on my downpipes isn't a requirement for the headers, I just do it to speed up removal as I don't ever reuse the factory exhaust manifolds and trash all of the old parts. It's just for convenience but you definitely remove the factory manifolds, cats and y pipe simply by unbolting all of the flanges. There is no playing around with the exhaust to get it to fit, you just remove all of the parts up to the cat back flange and bolt the new parts in. Below is a picture of the American Racing headers which is a pretty typical system for these trucks. That picture shows everything that they provide. The end connection is the spherical flange that mates up with your factory exhaust flange.

The benefit of the headers is the length of the primary tubes to assist with exhaust gas scavenging. The longer they are, the more torque/power you'll make. Shorty's will pretty much be a replacement for your exhaust manifolds only, while long tubes will replace the manifolds, downpipes and your catalytic converters. I've never done a set of Shorty's before, but I'd assume they'd be abit easier to install; although any of the times I've done my headers, the hardest flange to break apart was the exhaust manifold outlet itself as it's in a very difficult place to be able to reach all of the bolts. With the long tubes, I've found the easiest method is you unbolt the factory manifolds at the engine, then cut the pipes on the underside so the manifolds drop out, then just undo the rest of the piping.

Mod the exhaust? What do you mean by that? I've never had to mod the exhaust on any of my vehicles that I've put long tube headers on. Pretty much every kit on the market is a direct replacement for your exhaust manifolds, catalytic converters and Y pipe. Heck, on the trucks you could easily do the headers in afternoon if you have the tools available and a lift to help. Every kit I've used will bolt right up to your factory exhaust. All of the aftermarket companies I've dealt with offer full long tube kits for the trucks; stainless works, american racing, kooks, etc, etc.

As my truck has the Corsa with the dual exits under the bumper, I cut the pipes right after the axle and put on two turn downs. It actually looks a lot better and makes the volume bit more reasonable when idling or putzing around the neighbourhood.

If you combine the headers with the Corsa Touring, instead of the Sport, the truck is MUCH, MUCH quieter when cruising around and driving on the highway. Infact, I'm pretty sure it was quieter than my factory exhaust and drones a lot less as well. When you get on the gas it has a really nice bark, but it's still very reasonable. It was almost too quiet for me so I quickly installed a exhaust cutout and leave it partially open. The Sports on the other hand are freaking wild with headers. I would not recommend them unless you want to sound like a badass race car. I have headers + Corsa Touring on my 6.2L crew cab and AR headers with the Corsa Sport on my regular cab, so I've seen how they sound back to back. On the crew cab, I was originally planning on running the factory exhaust with the headers but there was way too much drone in that case. The factory muffler wasn't designed to deal with headers. I've done long tube headers on my last 5 vehicles, so I've lived with them on both my daily drivers and performance vehicles, and they are VERY, VERY easy to live with if done right.

I'm building myself a dual chamber one for my truck and can update once it's ready to go.

Based on my current experience with my 6.2L and 6 speed, I can definitely agree with this. My transmission tune is so aggressive that the truck will easily spin the tires on upshifts with the 3.43 rear end. I've been driving it this way for nearly 60000 km so far and it hasn't missed a beat. I definitely don't baby this truck. I typically pull a nice burnout in the office parking lot whenever leaving work. I'm sure the bosses are impressed.

That's a good question. I have the quote/pricing summary for the truck I plan to order, but at this time all of the pricing is blanked out.

This is whats listed on the GM order book page, it looks like it's standard since it says "included with the 6.2L".

The 2015, 6.2L, 8 Speed Denali's are getting the 3.23 rear end. A colleague of mine just had his ordered accepted yesterday for the truck.

Where are you getting your information? Even GM's own press release for the Silverado clearly mentions the 8L90E by name in the 1500's and gives a breakdown of the gear ratios:

It may be illegal, but the dealerships could care less. I've had dealers do this to me in Canada. Maybe it's different up here, but I ended up having to sell the vehicle because I couldn't get a dealership that wanted to touch the issue. One of them actually told me in the service bay when I showed up that it wasn't their problem and they wouldn't even look at it beyond basic servicing, i.e., oil change.

I'm in Calgary and I've never had any issues getting a Corsa exhaust, or any other car parts. Summit racing easily ships here, but it would be worth giving the guys at Davenport Motorsports in Calgary a shout as they could probably have it shipped directly to you.

This is what the Corsa Sport sounds like with the headers, haha, I love it. Surprisingly, that thing is absolutely quiet when on the highway. It definitely has a nice roar when you get on the gas, but no drone, even in V4 mode. I'd take some interior videos, but I put the truck away from the winter as the regular cab is my project vehicle and I don't want to deal with road salt, rock chips, etc. When I upgrade my 2009 to a 2014/2015 Sierra, I definitely plan on doing the same Corsa Sport + Headers combination.

Corsa is what I swear by. They have a unique, proprietary muffler design that allows for a very, very aggressive exhaust sound without any drone. The muffler is more of a straight pipe with expansion/dampening chambers cut into the OD. It allows them to specifically tune out the frequencies that result in drone, while preserving a loud, aggressive sound if thats what you like. I'm currently running the worst case scenario with my 2010 Silverado; Corsa Sport with American Racing Long Tube headers, and while the truck is offensively loud from the outside, it's absolutely quiet when cruising on the highway. The Corsa systems also have fantastic quality. I've installed them myself on my last 3 silverados, my Z06 and previously my Cherokee SRT8 and have always been very impressed with the construction and materials.

We do the hooning at Gull Lake, north of Red Deer in Alberta. It's much more fun when there is less snow on the lake. After awhile we end up with a thick layer of wet sticky snow and it really bogs the trucks down. In case anyone is curious, the truck with Dynatech Headers and a Corsa Touring is quieter for cruising on the highway than the OEM 6.2L exhaust. The factory 6.2L exhaust has a TON of drone and you don't realize it until it's gone. And as you can see, it sounds absolutely bad ass from the exterior. It has that very distinctive chevy small block + headers bark when you get on it.

This is a video showing how the 6.2L sounds with headers and a corsa catback. The crew cab is my 6.2L, the 2005 extended cab is a 5.3L with a magnaflow muffler welded in.