Any differences in exhausts between the SWB V8s?

[Mike534x]

Hey guys! I'm trying to do some research. My passenger side cat is failing, there is no loss of power but its rattling like crazy (banging on it with my hand sounds like a coffee can with nails). I'm 99% sure the insides are toast. Driver side is still solid, so trying to feel my options out. A quick search shows Walker (part # 16671) makes a complete setup, consisting of both the driver+passenger cats and a new y-pipe. Searching the part number shows its only compatible with the 06+ model years, Walker doesn't even list the Denali or 5.3 for 2005 on their website either. I called them, and while the person was nice on the phone they kept referring to it as a 3.5l and said they couldn't tell me. So my searching leads to nowhere. I've seen posts in the past about being able to use an SS exhaust on the 5.3, so I can't imagine the setup underneath is different or would prevent this from being used.

Should I chance buying it, or would it be easier to just grab 2 universal cats from Walker or Magnaflow and just have them cut/welded in place?

 

[Mooseman]

Looking at RA, they list some of them for 2005-2006 and don't differentiate between SWB and LWB.

2005 CHEVROLET TRAILBLAZER 5.3L V8 Catalytic Converter | RockAuto

RockAuto ships auto parts and body parts from over 300 manufacturers to customers' doors worldwide, all at warehouse prices. Easy to use parts catalog.

www.rockauto.com

I think the change from 05 to 06, at least for the 4.2, was the flange connection to the muffler. If it was me, I'd have universals welded in.

 

[Reprise]

Someone beat me by a few minutes... and they looked at the same site I did... and I think I'd advise same (universals). (note -- I did not compare pricing on two universals vs. full replacement! The full replacements run about $430 and up, btw)

It appears that what people are stocking, for anything '06-backward, assumes LWB. So the center pipe is a bit longer. Now, you *could* shorten it (or, a shop could)... you'd bolt on your new one, leave the end of the center pipe disco'd, and head down to your welder to have them cut out the 'extra' and weld back in place (while enjoying the sound from your (temporarily) open pipes. But that's a weld... and it appears you're looking for a bolt-on solution, from how I interpret your post.
Cut / weld the center pipe, or cut / weld in 2 new cats to your existing... kinda the same deal, right?

I did look up the TBSS part; it's the same as the 5.3 from the same timeframe. So that's an option. BUT -- it looks like they might have changed the size / shape / orientation of the cats. The pic below will hopefully illustrate this (I could be wrong, so continue the research, if desired). The risk for you is that you'd have the correct total length pipe, but the cats wouldn't fit in that snug little engine bay (which didn't change at all, but it's a consideration I'm bringing up).

The big difference between the '06-forward and the earlier ones, is that the end terminates in a flex pipe, similar to the 4.2 pipes that Moose mentioned. So that's why they list different parts. They also list some sort of "precious metal wash" process (which shouldn't make a bit of difference as far as fitment, unless it necessitated a different cat shape be used), so that's another 'difference' between the earlier / later models.

Here's the screencap I made of the three. The first is for a LWB; the second is from the same manufacturer, but for the SWB (different part #), and the third is your Walker, for comparison. Unfortunately, Rock only provides one pic for each of these. Note the difference between the cat locations / shapes between #1 and the others.

Hope this helps.

 

[TollKeeper]

So there is a difference in the 2005-2006, what exactly it is? I have no idea

GM Part # for the 2005 GMC Envoy Denali for the y-pipe with cats is 15119821 <- No longer made, but is available... for some large $$
GM Part # for the 2006 GMC Envoy Denali for the y-pipe with cats is 15808213 <- Readily available

 

[Mike534x]

@Reprise Ah I see! I didn't spot the orientation before, I thought maybe it looked a little off from the orientation the pictures were taken.

To avoid any headaches, I ordered an universal Walker cat #93253 to have welded in. It looked like Magnaflow makes one but its about $800-1000. I'd rather stick with replacing the cat and just live with it.

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