1997 K1500 5.7 suburban exhaust compatibility

[dasburb]

Hi everyone,

I have a 1997 Suburban which has a vortec 5.7 and a style of exhaust which has two pipes that are separate leading into the muffler. It looks like the picture below

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What I'm wondering is if a slightly newer exhaust system from a 99' would be intercompatible AND allow for me to pass smog in California. My old exhaust is cracked at the right side O2 sensor, and the right side cat

The potential new exhaust looks like this:

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Will this work and pass smog? I haven't been able to find an answer anywhere. Thank you if you can offer insight!

 

[Mawfuqqa]

97 should be obd1 dyno smog. Technically you might not (visually) but a good amount of shops don't care as long as no cel and has cats at all.

 

[b454rat]

96-up is OBDII, meaning you get f'd at inspections and CEL....

 

[HotWheelsBurban]

My '99 C1500 Burb with 5.7 has the same exhaust system yours did originally. My Burb was built in Mexico, probably to GM 49 state emissions specs. Bought it used but afaik it's been in Texas all its life. The factory muffler is huge and has two inlets, one from each bank. There's a big flange in the pipes just past the rear cars, that has 3 bolts and a gasket. Muffler and inlet pipes are back from this, and the muffler has one outlet that becomes the tailpipe. I know on the 80s square body trucks, they had a 2 in/2 out muffler and twin tailpipes, but I haven't seen that on 400s.
Since you are in Cali, you'll need to keep it as close as possible to stock, to be sure to pass visual inspection and smog testing. Texas has no smog/emissions inspections for any vehicles 25 years old or older, unless it's a commercial vehicle. And our regular safety inspection goes away in January 2025.....
More reasons to like the Lone Star State. Our traffic still sucks in the urban areas, but there are usually several alternate routes to get most places.

 

[99xcss4]

My '99 C1500 Burb with 5.7 has the same exhaust system yours did originally. My Burb was built in Mexico, probably to GM 49 state emissions specs. Bought it used but afaik it's been in Texas all its life. The factory muffler is huge and has two inlets, one from each bank. There's a big flange in the pipes just past the rear cars, that has 3 bolts and a gasket. Muffler and inlet pipes are back from this, and the muffler has one outlet that becomes the tailpipe. I know on the 80s square body trucks, they had a 2 in/2 out muffler and twin tailpipes, but I haven't seen that on 400s.
Since you are in Cali, you'll need to keep it as close as possible to stock, to be sure to pass visual inspection and smog testing. Texas has no smog/emissions inspections for any vehicles 25 years old or older, unless it's a commercial vehicle. And our regular safety inspection goes away in January 2025.....
More reasons to like the Lone Star State. Our traffic still sucks in the urban areas, but there are usually several alternate routes to get most places.

on tbi trucks I do not know if it was optional on the blazer/tahe/yukon/suburban but on all the pickups all cab and bed styles 1500 2500ld 2500 8 lug 3500 2wd and 4x4 had a dual tail pipe option I do not know what the pipe diameter was just that that the muffler was single in dual out both pipe on the passenger side and that it was standard on the 90-93 454ss

 

[1998_K1500_Sub]

Hi everyone,

I have a 1997 Suburban which has a vortec 5.7 and a style of exhaust which has two pipes that are separate leading into the muffler. It looks like the picture below

I'm not sure why you want to try to use that other (1999?) Y-pipe you pictured. YOUR Y-pipe is fine.

Your problem lies with the back half ("cat back") of the exhaust system. Read on...

One solution to your problem would seem to be:

- separate the two flanges which are bolted together (see arrow in picture, below)

- with the rear flange removed, set the front Y-pipes aside

- remove the remainder of the exhaust system from the vehicle (the pipes into the muffler, etc., on back... the "cat back" portion)

- take the rear flange, with broken pipe sections and the rest of the exhaust that you've removed (the "cat back" portion), to a welding shop and have them re-attach the flange to the pipes where they broke.

- If necessary, you can provide the welding shop with small lengths of stainless exhaust pipe to use as filler, e.g., as sold on Amazon (see link below and note the variety of sizes available):

Stainless Steel Universal Exhaust Adapter

https://www.amazon.com/dp/B09XWW6FNT?th=1

You must be registered for see images attach

Others here on GMT400 may offer similar solutions.

ALTERNATIVELY, the rear muffler section, from the flange back, may be available complete from RockAuto or from other third-parties as a "cat back" exhaust. Using these options you may be able to simply (for $$$) replace it.




I had a similar problem recently on my Suburban, where the front pipe broke here (see arrow in picture below). To repair it, I bought a short segment of SS pipe, with 2"ID and 2" OD, from Amazon and had it welded-in to replace the section which had broken. This required me to separate the flanges and pull the front Y-pipes off. It was basically the same repair that you need to do, except mine was on the front pipes and yours is on the back pipes.

You must be registered for see images attach

Here’s a picture of mine, completed.

You must be registered for see images attach

You must be registered for see images attach

 

[GoToGuy]

Look in a parts diagram with expanded illustrations. And the model that's equipped with and for California Carb emissions. Just stop with 48 crap. If you don't live here you got no dog in the hunt. They are different than other 48.
When comes to anything related to smog we in Socialist hell of California always have to check the " notes, asterisk, addendum, special listings, to make sure we don't offend the " CARB gods "
A GM parts dealer that has online parts lookup, that has the illustration, make sure it's California Emissions option. The cats are higher level of emissions reduction. California has tighter rules, that's why there's 48 state and or California emissions RPO option .

 

[Sean Buick 76]

Is moving out of California an option lol?

 

[GoToGuy]

If your single, also known as potential rolling stone. Then yes.
Out of my great grandfather's descendents, I am the only one still living in California. Grandparents, Parents, Aunts & Uncles, Cousins, Brothers, Sisters . All have moved out. When my wife retires, we are going somewhere else. It's a tragedy, they've ruined this state. They ruined my old high school. They've destroyed the rural lifestyle we grew up with.

 

[dasburb]

I'm not sure why you want to try to use that other (1999?) Y-pipe you pictured. YOUR Y-pipe is fine.

Your problem lies with the back half ("cat back") of the exhaust system. Read on...

One solution to your problem would seem to be:

- separate the two flanges which are bolted together (see arrow in picture, below)

- with the rear flange removed, set the front Y-pipes aside

- remove the remainder of the exhaust system from the vehicle (the pipes into the muffler, etc., on back... the "cat back" portion)

- take the rear flange, with broken pipe sections and the rest of the exhaust that you've removed (the "cat back" portion), to a welding shop and have them re-attach the flange to the pipes where they broke.

- If necessary, you can provide the welding shop with small lengths of stainless exhaust pipe to use as filler, e.g., as sold on Amazon (see link below and note the variety of sizes available):

Stainless Steel Universal Exhaust Adapter

https://www.amazon.com/dp/B09XWW6FNT?th=1

You must be registered for see images attach

Others here on GMT400 may offer similar solutions.

ALTERNATIVELY, the rear muffler section, from the flange back, may be available complete from RockAuto or from other third-parties as a "cat back" exhaust. Using these options you may be able to simply (for $$$) replace it.




I had a similar problem recently on my Suburban, where the front pipe broke here (see arrow in picture below). To repair it, I bought a short segment of SS pipe, with 2"ID and 2" OD, from Amazon and had it welded-in to replace the section which had broken. This required me to separate the flanges and pull the front Y-pipes off. It was basically the same repair that you need to do, except mine was on the front pipes and yours is on the back pipes.

You must be registered for see images attach

Here’s a picture of mine, completed.

You must be registered for see images attach

You must be registered for see images attach

Thank you very much for the explanation. I guess I didn't describe my problem well enough.

The reason I'm wondering about a swap is I have a 99' CARB compliant cat system I got for free and my 97' is absolutely SMOKED. There are massive cracks around the entry to the passenger-side cat, and a large crack around the passenger side forward 02 sensor.

Also, the exhaust-to-header bolts are VERY rusted and I didn't want to risk breaking the studs/headers myself when I dropped the transmission to rebuild it. To do that I also had to cut the cross-pipe. All of the exhaust sans cross pipe is still on the car; I don't have an induction heater and don't wanna risk it with a torch.

Maybe it's just a "muffler shop has to just weld it all back together and put on stainless nuts" situ and I'm being overly paranoid. But it would be a minimum of 4 welds to put it all back together.

I can do many things, but adding learning to weld would be overwhelming at this point as I'm in the midst of a career change into mechanical engineering. It's the first time I've had to work on exhaust and I'd rather just pay someone than spend a month of what little time I have getting it right. If I can just have someone remove the bolts and bolt in the new y pipe and a muffler myself I'd rather do that.

I hate that there is a regulatory problem too; that's part of why I didn't just 4L80 swap.

I just would like to have everything skookum vs being kluge-fixed as the interior of the car is immaculate and everything else is pretty well done and ready for another 100k-200k miles.

I'm not sure why you want to try to use that other (1999?) Y-pipe you pictured. YOUR Y-pipe is fine.

Your problem lies with the back half ("cat back") of the exhaust system. Read on...

One solution to your problem would seem to be:

- separate the two flanges which are bolted together (see arrow in picture, below)

- with the rear flange removed, set the front Y-pipes aside

- remove the remainder of the exhaust system from the vehicle (the pipes into the muffler, etc., on back... the "cat back" portion)

- take the rear flange, with broken pipe sections and the rest of the exhaust that you've removed (the "cat back" portion), to a welding shop and have them re-attach the flange to the pipes where they broke.

- If necessary, you can provide the welding shop with small lengths of stainless exhaust pipe to use as filler, e.g., as sold on Amazon (see link below and note the variety of sizes available):

Stainless Steel Universal Exhaust Adapter

https://www.amazon.com/dp/B09XWW6FNT?th=1

You must be registered for see images attach

Others here on GMT400 may offer similar solutions.

ALTERNATIVELY, the rear muffler section, from the flange back, may be available complete from RockAuto or from other third-parties as a "cat back" exhaust. Using these options you may be able to simply (for $$$) replace it.




I had a similar problem recently on my Suburban, where the front pipe broke here (see arrow in picture below). To repair it, I bought a short segment of SS pipe, with 2"ID and 2" OD, from Amazon and had it welded-in to replace the section which had broken. This required me to separate the flanges and pull the front Y-pipes off. It was basically the same repair that you need to do, except mine was on the front pipes and yours is on the back pipes.

You must be registered for see images attach

Here’s a picture of mine, completed.

You must be registered for see images attach

You must be registered for see images attach