1999 K1500 Replacement Catalytic Converter, Bank 2

All,

Need to replace the cat on bank 2 on my 1999 K1500 w/ the 350. I've heard that quality cats can be had online for ~$100, would you guys mind directing me to these websites? Please and thank you.

-Bob

Amazon, Summit, Jegs...and dozens of others.

Select product based on your location/emissions laws, pipe inlet and outlet size/configuration, and manufacturer reputation.

Keep in mind that anything in that price range is going to be a universal cat and will require cutting and welding to install. Which may not be the easiest thing in the world depending on your specific truck and Y-pipe setup. Magnaflow makes a bolt in stainless Y-pipe with cats for around $450, or single weld-in universal cats for around $125. Here's some links, I looked up part numbers for a '98 K1500 5.7 as the whole '99+ late model GMT400 lookup thing seems to confuse the Magnaflow site and bring up GMT800 parts.

Part number 23453 (bolt in pipe with cats):
https://www.amazon.com/MagnaFlow-23453-Catalytic-Converter-compliant/dp/B000JKNGY8

Part number 99004HM (weld in universal cat):
https://www.amazon.com/MagnaFlow-99004HM-Universal-Catalytic-Converter/dp/B001HMAXQG

df2x4 said:

Keep in mind that anything in that price range is going to be a universal cat and will require cutting and welding to install.

Click to expand...

Cutting...absolutely.

Welding is optional. God bless stainless-steel band clamps. (Yes, I specifically noted "stainless steel", I had a non-Stainless band clamp rot out on me. Until I saw the mess years after installation, I didn't know that band clamps weren't ALL stainless.)

Something like THIS, for pipes that butt together with no overlap:
https://www.summitracing.com/parts/sum-683250/overview/


There are many different brands of essentially the same thing. A minor but important variation is the "lap" clamp. If the two pipes overlap, so that one slides inside the other, you want the "lap" version.

https://www.summitracing.com/parts/sum-681250/overview/

Schurkey said:

Cutting...absolutely.

Welding is optional. God bless stainless-steel band clamps. (Yes, I specifically noted "stainless steel", I had a non-Stainless band clamp rot out on me. Until I saw the mess years after installation, I didn't know that band clamps weren't ALL stainless.)

Something like THIS, for pipes that butt together with no overlap:
https://www.summitracing.com/parts/sum-683250/overview/

You must be registered for see images attach

There are many different brands of essentially the same thing. A minor but important variation is the "lap" clamp. If the two pipes overlap, so that one slides inside the other, you want the "lap" version.

https://www.summitracing.com/parts/sum-681250/overview/

You must be registered for see images attach

Click to expand...

Would there be enough room to use clamps in this application? It seems like the angles of the factory Y-pipe would make that difficult. I just didn't even consider it as an option because it looks like a tight squeeze in there.

I had a downpipe crack recently, and had welded in replacement cats in the past, so I decided to get a whole new downpipe/cat assembly. Rock Auto has a Bosal one that fits your truck for right around $250, where the Walkers and others all seem to run around $450. The quality was much better than I expected- I don't remember seeing it in the description, but the whole thing turned out to be stainless. It could save you some hassle, and if one cat is bad, the other will probably follow soon.

df2x4 said:

Would there be enough room to use clamps in this application? It seems like the angles of the factory Y-pipe would make that difficult. I just didn't even consider it as an option because it looks like a tight squeeze in there.

Click to expand...

Maybe...maybe not. Easy enough to slide under and measure.

Had acres of room on my single-cat '88.

If I understand correctly, you guys are suggesting I pick up one of those K1500 pre-cat exhaust pipes that includes both Bank 1 + Bank 2 cat and bolt it up to my stock muffler. This way, I'm future-proofed against the Bank 1 converter inevitably failing shortly after replacing the Bank 2 converter.

With this setup, I'd still have the option to remove the stock muffler and add a cat-back dual exhaust system (Flowmaster 40 or Gibson side-exit, most likely) down the road, correct?

In a nutshell, yes. If it were my truck I'd replace the entire Y-pipe assembly with one of those Magnaflows I linked (They have a different part number if you're in CA or NY and need a CARB compliant version) to avoid replacing the second cat shortly after the first.

My red truck is a V6 so it only has one cat, but I run a similar Magnaflow Y-pipe on it. Everything bolted up nicely and the bends in the pipe look much nicer than the factory piece. It worked fine with the factory exhaust and muffler but I later switched to a Gibson 3" single side exit.

I got mine on ebay looked up a 99 Cadillac escalade 5.7l and got the complete wye pipe assembly complete with cats for under 200 bucks direct bolt on no cutting required

rc64597 said:

All,

Need to replace the cat on bank 2 on my 1999 K1500 w/ the 350. I've heard that quality cats can be had online for ~$100, would you guys mind directing me to these websites? Please and thank you.

-Bob

Click to expand...