HEADERS, MANIFOLDS & CATS

[Meccanoble]

As I build the courage to do my own cat replacements, I think of the biggest issues people have regarding those manifold bolts breaking/stripping where it connects to y-pipe. I wonder, wouldnt it be easier to buy new/upgraded manifolds and remove from there instead of the y-pipe.

Also, what is the cheapest reliable high flow cats you would recommend? I am stock but hear high flow cats are more fuel efficient. The alternative is stock. Car was in south so no rust. Was tempted to buy cats and have them welded on vs full exhaust piping vs OEM. for a stock car, which way would you go? No intentions of making car faster.

 

[swathdiver]

Replacing the manifolds and or bolts is good preventive maintenance. At this age if they haven't broken, they soon will. I had a gasket blow on the passenger side a couple of years ago and it took quite a bit of planing to get the flange smooth again. Now there is a broken bolt on the driver's side and am going to just replace the entire manifold so as not to have to fool with planing it flat for a good seal. Going to use Fel Pro hardware, ES75106 and ES75120.

The Magnaflow cats and y-pipe comes with new left and right exhaust manifold gaskets. If your clamp is corroded get a Walker 36522.

I'm leaning heavily towards putting a 6.2 in the truck and if I do, will need new cats and y-pipe and new, larger, 3.5" exhaust.

 

[Meccanoble]

Replacing the manifolds and or bolts is good preventive maintenance. At this age if they haven't broken, they soon will. I had a gasket blow on the passenger side a couple of years ago and it took quite a bit of planing to get the flange smooth again. Now there is a broken bolt on the driver's side and am going to just replace the entire manifold so as not to have to fool with planing it flat for a good seal. Going to use Fel Pro hardware, ES75106 and ES75120.

The Magnaflow cats and y-pipe comes with new left and right exhaust manifold gaskets. If your clamp is corroded get a Walker 36522.

I'm leaning heavily towards putting a 6.2 in the truck and if I do, will need new cats and y-pipe and new, larger, 3.5" exhaust.

I'm at 247k miles but was a Southern car all of its life so I dont see any rust or corrosion concerns. Is this where short/long tube headers come into play? I wonder if a 1 set that handles everything is available (headers/ypipe/cats).

Also, on a stock truck, is it even helpful/necessary?

 

[swathdiver]

I'm at 247k miles but was a Southern car all of its life so I dont see any rust or corrosion concerns. Is this where short/long tube headers come into play? I wonder if a 1 set that handles everything is available (headers/ypipe/cats).

Also, on a stock truck, is it even helpful/necessary?

@badandyturbo had a stock Tahoe with long tubes and a catless y-pipe and his motor picked up at least 20 horses to the rear wheels at the drag strip. Myself and several others on here witnessed it in person. His goal was to use all Amazon parts, I think they were pacesetters or equivalent. He has since sold the Tahoe and gotten a Flex.

 

[Meccanoble]

@badandyturbo had a stock Tahoe with long tubes and a catless y-pipe and his motor picked up at least 20 horses to the rear wheels at the drag strip. Myself and several others on here witnessed it in person. His goal was to use all Amazon parts, I think they were pacesetters or equivalent. He has since sold the Tahoe and gotten a Flex.

Do you have a recommendation for long tube headers with cats?

 

[Geotrash]

He has since sold the Tahoe and gotten a Flex.

So that raises questions of judgment in my mind

 

[swathdiver]

Do you have a recommendation for long tube headers with cats?

Not really. There are guys on here with Kooks and American Racing and some others, ask them. @randeez

 

[Meccanoble]

Some people mentioned power increase with shorty headers i guess with wider diameters. I'm thinking a replacement manifold or shorty headers may be good to avoid the ticking sound some people hear at the minimum.

Anything wrong with these?

https://www.amazon.com/Exhaust-Headers-Stainless-2008-2013-Silverado/dp/B09VP7N9WC/ref=psdc_15726911_t2_B09VD8SJQ6

 

[ilikemikes]

What was your results here?

 

[Foggy]

If your engine itself is stock (no cam, head work, stroker, forced induction)
then IMO you would be wasting a lot of money to change out the manifolds for
headers. There WILL be more expense than just the headers. You won't gain
anything with headers until you have a custom tune done to take advantage.
If you cats are toast (meow) then you have diff options on the cats w. Y pipe...
Stock replacement stuff is fine