Rocket Man's 2008 Bagged CC Silverado Build AKA "THE MACHINE"

[07Burb]

Well it’s not looking good for long tubes on this truck. I still have some more test fitting but I don’t see any way for these to work with the way the frame, trans mount and crossmembers are. I’m thinking the best thing for me to do is get some shorties and then swap out the muffler for something better, maybe a Borla. I might be able to have the cats replaced with some high- flow ones so a shop will still work on it and build something different but I just have no room. Sucks. Anybody know of a decent set of shorties? Kooks sells a set but they want a grand. For shorties!

So obviously, it looks like the exhaust shop you went to originally (the non hack shop) was correct upon original inspection? Glad you didn't go all around town to some less reputable shops until you got a "yes I'll do it answer". As you most likely know, long tubes are big and bulky so I'm sure what you're running into with your truck is not uncommon considering the level of modifications it's already had. Going shorty is probably the best bet so that you can keep the pipe as close to the block and the underside of the truck as possible as it goes towards the rear of the truck.

 

[pwtr02ss]

What kind of power will the shorties make over the manifolds? Seems like a lot of work for a very minimal gain, if that's the case.

 

[Rocket Man]

So obviously, it looks like the exhaust shop you went to originally (the non hack shop) was correct upon original inspection? Glad you didn't go all around town to some less reputable shops until you got a "yes I'll do it answer". As you most likely know, long tubes are big and bulky so I'm sure what you're running into with your truck is not uncommon considering the level of modifications it's already had. Going shorty is probably the best bet so that you can keep the pipe as close to the block and the underside of the truck as possible as it goes towards the rear of the truck.

In all honesty I was only asking him to possibly modify the y-pipe and then build something from there back but I have to admit he was right. I was only giving it a 50% chance but i tried installing the passenger header today and the fact they lowered the engine in the bay (in order to fit under the hood with the body drop) became apparent when it hit the frame so I couldn’t even bolt it to the block without cutting into the frame. Which I would have done except the next step, to see if the y would fit, failed as well. First, where it connects to the header is already below my frame (which lays on the ground) and then the 3” pipe that crosses over to the driver side does so under the trans pan, which has only 2 1/2” between it and the bottom of the frame so that would have to be modified to a flattened oval 2” high. Then the trans mount is in the way of the main pipe exiting to the muffler so that would have to be dealt with somehow. It’s just too much.

What kind of power will the shorties make over the manifolds? Seems like a lot of work for a very minimal gain, if that's the case.

I’m mainly looking to get a decent sound and get the catalytic converter away from the underside so it doesn’t rattle. It just has a lousy sound, so even shorties will help I’m hoping. And they are direct manifold replacements so they’re really no work at all. I either reinstall my stockers or install shorties. Everything else will bolt right up. So I think I’ll do that except make more clearance where the driver cat hits the underside and maybe have dude rebuild from the cats back, possibly replace them with high flows.

 

[07Burb]

Just flip the headers up and stick the exhaust out of the hood. Problem solved

 

[Rocket Man]

Just flip the headers up and stick the exhaust out of the hood. Problem solved

I’ll wait until I buy a snail to do that!

 

[Rocket Man]

Ordered the Doug Thorleys, they’ll be here Friday. Compromises.

 

[Rocket Man]

On a positive note, all the exhaust manifold bolts came out without breaking off in the block! I have ARP bolts to go back in so I can check that worry off my list. It’s got to be one of the worst thing about these engines, broken exhaust manifold bolts causing leaks. There’s still 2 on The Beast that I couldn’t get out and had to use the clamps on.

 

[iamdub]

Well it’s not looking good for long tubes on this truck. I still have some more test fitting but I don’t see any way for these to work with the way the frame, trans mount and crossmembers are. I’m thinking the best thing for me to do is get some shorties and then swap out the muffler for something better, maybe a Borla. I might be able to have the cats replaced with some high- flow ones so a shop will still work on it and build something different but I just have no room. Sucks. Anybody know of a decent set of shorties? Kooks sells a set but they want a grand. For shorties!

Shorties really aren't gonna change the sound much at all. You may get more sound from up front due to the thinner steel as compared to the cast iron manifolds, but that's about it. Factory cats ARE high flow cats. Aftermarket cats are the same thing, just with less of the ceramic media and often times less of the actual catalyst on that media so they're more prone to "catalyst inefficiency" code sooner or later. I havec a set of Magnaflow cats and my OEM cats if you wanna see a side-by-side comparison. The aftermarket listing their cats as "high flow" is purely for marketing.

 

[iamdub]

Ordered the Doug Thorleys, they’ll be here Friday. Compromises.

I have their Tri-Ys. Fit was excellent. Just had that goofy flange discrepancy with the Y-pipe. As far as the headers themselves, I'm surprised at how well they control the sound. They don't have the common header "ticking/ringing" from the exhaust colliding in the collectors and radiating through the thin steel. I can't really tell any difference in engine bay heat as compared to the cast manifolds, either. According to DT, they're coated three times on the inside and five times on the outside. I'd imagine their shorties to have the same treatment.

 

[Doubeleive]

magnaflow cat's are smaller than stock at least the ones the shop put on my 12 are