Exhaust Question- 1999 k1500 Suburban, 350ci

[Coveman]

I’m ready to replace the replacement exhaust system (flowmaster cat-back) with a stainless magnaflow system. The magnaflow fitment asks whether my system has single or double pipes going into my muffler.

The flowmaster had a y-pipe design (two flanges for the cats) and a single muffler inlet so I chose that configuration from magnaflow. Turns out the magnaflow comes with a single flange pipe to connect the cats with the muffler, but i need dual flange to connect with the two cat pipes. Returning this for the other set up will cost a small fortune in shipping costs.

My question is can I purchase a different cat system that will bolt on to my stock manifolds and the new single pipe system? Not sure if the single flange configuration for my truck is for 2 wheel drive or if gm made 2 different exhaust systems for the k1500 trucks.

Thanks in advance!

 

[b454rat]

You can buy new pipes from the manifolds back with cats, flowmaster sells them. It's supposed to be a direct replacement. Jegs sells an offroad system which is pretty much the same, just no cats. I'm not sure how your truck is set up, but 305 trucks have one cat, which obviously is a different system. Not quite sure what the flow or Gibson you looks like but if it has 2 pipes welded to a flange, then you should be able to get a cat back for it. I bought summitracing headers, Jegs offroad pipes, and think it's a Gibson cat back that was on vehicle when I bought it. Bolted up OK, lil tweaking, but it's on!!!! Hoping to fire it up soon.

 

[L31MaxExpress]

Buy your replacement exhaust for a 1-ton. Magnaflow makes the larger headpipes with high flow cats. On the truck I did I had to repin the rear 02 sensor wires at the PCM. Bank 1 and Bank 2 rear 02 sensors were swapped in location on the heavier trucks compared to the 1/2 ton I put it on.

 

[b454rat]

Yeah those pipes are like 600 bucks if not more. I wanted to do the same thing. Summit and Jegs have the same size pipes for any truck, 2 1/4", so looking up for a 1 ton is the same part number for a 1/2"

 

[L31MaxExpress]

Yeah those pipes are like 600 bucks if not more. I wanted to do the same thing. Summit and Jegs have the same size pipes for any truck, 2 1/4", so looking up for a 1 ton is the same part number for a 1/2"

A little over $500 for the pair if you get them from Rockauto. Bosal and Magnaflow are the same.

 

[Schurkey]

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Made in several inlet/outlet sizes.

For example, https://www.summitracing.com/parts/mpe-10768. $33

Cut and weld to fit your system. Or use band clamps if you have enough room.

 

[Coveman]

Thanks gents!