'97 C1500 4.3L V6 Catalytic Converter/Y-Pipe Recommendations

[df2x4]

100k mile life? Really? My 99 NBS 4.3 Vortec has 255k. I KNOW it is original. By buddy has another '01 4.3 with close to 400k miles!

I also have 3 other GM trucks with 240k (GMT 400,) 208k (GMT 800,) and 168k (GMT 800) miles. I don't know the history on those as I bought them not that long ago with all those miles, but when I've looked under there, the catalytic converters look factory. If any one of them fails, I'm getting a factory one from a parted out truck!

My brother has a 90 C1500 and my Dad has had a 89 C1500, and I don't recall any of them failing catalytic converters. Both over 150,000 miles each.

The only catalytic converter I know personally that has failed was a nephew's S10 with 4.3 Vortec that got plugged. He's not too good about maintenance. I told him he needed to figure out why it had plugged, but he just cut them off and kept trucking, LOL.

I got a little over 100K out of the factory one on this truck, but the ones on my Suburban are still kicking at 24 years old and 160K+ miles. My dad's '06 3500 has over 250K on the original cats. I think I'm just particularly unlucky with cats (among other things). The Magnaflow doesn't seem to be terribly clogged up, but it's rattling around pretty good in the housing.

I did consider just deleting the cat entirely and having Black Bear alter my tune to disable the rear O2 sensors, but I think I've decided against that. I don't want to smell like gas every time I drive the truck, or worry about passing state inspections. Plus I don't think anyone makes an "off-road" catless Y-pipe for the '96+ V6 exhaust system so I'd have to have one welded up if I went that route.

 

[df2x4]

After spending a large chunk of this evening researching the available options I'm seriously thinking about just rolling the dice on another one of the exact same Magnaflow 23457s. I do know the definition of insanity... But nothing else on the market has full stainless steel construction and nice looking bends/welds with that kind of warranty. I hate to buy a duplicate of something I've had bad luck with once already (4L60E syndrome) but in this case there doesn't appear to be any better option on the market. The Flowmasters I linked earlier are the only thing that look close in terms of build quality. Still considering those as well.

 

[east302]

I actually just read that Magnaflow now owns Bosal's USA operations, plus I found a review for the Bosal on Amazon which says the flange bolt holes are improperly sized. Considering this info I think I'm leaning more towards the Walker 50409.

I read the opposite when looking for an inexpensive set for a 350. I think it was the Magnaflow that had misaligned bolt holes mentioned in several reviews while the Walker had to be bent to fit to the headers. The Bosal got decent reviews (or, at least, some guy on Amazon said it fit his Suburban without a lot of issues) so I went with that. That’s a 350, though.

Haven’t put it in, watch it be all jacked up with half of it being measured for a Dodge or something, lol.

It might not hurt to call Magnaflow and see if they’ll help you out on a price. Good luck.


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[SUBURBAN5]

I read the opposite when looking for an inexpensive set for a 350. I think it was the Magnaflow that had misaligned bolt holes mentioned in several reviews while the Walker had to be bent to fit to the headers. The Bosal got decent reviews (or, at least, some guy on Amazon said it fit his Suburban without a lot of issues) so I went with that. That’s a 350, though.

Haven’t put it in, watch it be all jacked up with half of it being measured for a Dodge or something, lol.

It might not hurt to call Magnaflow and see if they’ll help you out on a price. Good luck.


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Same here. But 5.7 vortec. I will say this the bosal can be a tiny bit wider. Meaning if you install the left or right side first you have to push the opposite side to line up straight to the flange... holes are fine , everything else lines up but it can be a worknout while laying on your back. Btw that's with my 4" lift. Not trying to scare anybody because I like them. Just telling you my experience with them. Last thing I'll leave you with is the flange. Stock flange had a thicker maybe cast flange while bosal or aftermarket cc have typically a 1/4 or so steel flange. Not a big deal but over time if you tighten it too tight it can bend

 

[df2x4]

I read the opposite when looking for an inexpensive set for a 350. I think it was the Magnaflow that had misaligned bolt holes mentioned in several reviews while the Walker had to be bent to fit to the headers. The Bosal got decent reviews (or, at least, some guy on Amazon said it fit his Suburban without a lot of issues) so I went with that. That’s a 350, though.

I think there's just so much variation in how people have their exhaust systems set up that none of the available options will be a perfect fit for 100% of people. All the reviews on the V6 stuff seem to be fairly mixed.

Haven’t put it in, watch it be all jacked up with half of it being measured for a Dodge or something, lol.

I will say this the bosal can be a tiny bit wider. Meaning if you install the left or right side first you have to push the opposite side to line up straight to the flange...

These two points right here are part of why I'm primarily looking at the Magnaflow and the Flowmaster now. The two piece design allows a little more wiggle room when fitting everything up. I'm running shorty headers so my measurements between the collectors might be a tiny bit different from the factory manifolds.

 

[SUBURBAN5]

I think there's just so much variation in how people have their exhaust systems set up that none of the available options will be a perfect fit for 100% of people. All the reviews on the V6 stuff seem to be fairly mixed.





These two points right here are part of why I'm primarily looking at the Magnaflow and the Flowmaster now. The two piece design allows a little more wiggle room when fitting everything up. I'm running shorty headers so my measurements between the collectors might be a tiny bit different from the factory manifolds.

I had shorty headers. Pace setter. Gave up on them and when back to oem. Worlds difference in changing plugs and tightening the cc. Btw heres a pic of mine used. Just incase

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[df2x4]

I had shorty headers. Pace setter. Gave up on me and when back to oem. Worlds difference in changing plugs and tightening the cc.

Mine are Pacesetters too. For anyone else with a '96+ 4.3L V6 reading this, DO NOT buy Pacesetter shorty headers! They're machined improperly straight out of the box, to the point that you have to cut a chunk out of one of the flanges to clear the coolant temp sensor. It's a miracle that mine don't leak. I'm considering going back to factory manifolds while I'm taking care of the cat issue, but I'm going to have to do a lot of digging in the parts piles to find mine. Hope I didn't throw them away in the move years back...

 

[SUBURBAN5]

Mine are Pacesetters too. For anyone else with a '96+ 4.3L V6 reading this, DO NOT buy Pacesetter shorty headers! They're machined improperly straight out of the box, to the point that you have to cut a chunk out of one of the flanges to clear the coolant temp sensor. It's a miracle that mine don't leak. I'm considering going back to factory manifolds while I'm taking care of the cat issue, but I'm going to have to do a lot of digging in the parts piles to find mine. Hope I didn't throw them away in the move years back...

I hear you. Had to go to the old shed and pull out my original manifolds lol. New hardware and they went in. I recommend mahle gasket btw. Felpro good too but I dont like the ends.

Heres the ends on the pacesetters

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[east302]

Hope I didn't throw them away in the move years back...

Lol, you probably did.

That’s how it works at my house, at least.


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[1997]

i used magnaflow on my 97, flowmaster for the 95, imo, neither were as good as i expected.
pretty crappy welds, not round flanges and weld splatter in the 02 sensor threads etc.
fit pretty good thou.
having said that, the magnaflow were slightly better imo compared to the flowmaster.

Magnaflow's O2 sensor passenger side closest to the exhaust manifold is a real pain in the ass to get in, so if you go that route put them in 1st. (stock pipe O2 sensor was easier to access)

i would also suggest getting the 2 peices welded once you get them installed.

my 97's stock C converter broke apart and was rattling around inside. i kept the original since i think i would have it cut out and a new CC welded in that, the stainless pipes were in good shape and way better quality than either MF or FM. (if the MF craps out like yours)

sorry not much help, just more info.