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12-29-2017, 11:35 AM | #1 |
Senior Member
Join Date: Sep 2004
Location: Wakaw, Sask, Canada
Posts: 3,170
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Exhaust help! 5.7 vortec plugged cats..worth paying for larger diameter replacement??
So I bought a pretty clean (for here anyway, no rust etc) 98 z71 with the 5.7. Got a PO430 code and after replacing the O2 sensors friend suggested it is time to replace the cats which have lived for 277000km.
I know the factory piping is pretty tiny, but is it worth it to have a slightly larger set fabbed up? Can find stock replacement easy enough, but nothing larger, say like a 2-1/4. Would there be any real gains? Headers worth it? It is a winter daily driver so I am not sure how much I want to spend on this thing yet. Other than changing out the poppet injector arrangement it won't see any engine mods. Looked into a 3/4 ton setup which is larger, but shops here say it can't be used as it is different, even though the truck body and engine is the same? confused.. So is it worth it to spend some coin in this area? Having a shop fab a complete system up will prob be over $1000. Stock replacement of bad area about $500. Anyone?
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"You can take the man out of PA, but you can't take PA out of the man" |
12-29-2017, 12:11 PM | #2 |
Cruzzzn' Vet
Join Date: Jan 2005
Location: Porterville,Ca.
Posts: 1,918
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Re: Exhaust help! 5.7 vortec plugged cats..worth paying for larger diameter replaceme
Go with Magnaflow cats, they flow the best, have a 3" single exhaust on my 83 with a Magnaflow.
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12-29-2017, 04:18 PM | #3 |
Senior Member
Join Date: May 2004
Location: Binghamton, NY
Posts: 3,453
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Re: Exhaust help! 5.7 vortec plugged cats..worth paying for larger diameter replaceme
I don't see how it is different. I had a 99 CCSB that had a 350 and bigger pipes. Now I have a 98 Tahoe with smaller pipes. Maybe their thinking the bigger pipes will flow at higher Rs than the smaller pipes. I had headers on the crew, and shows the same thing for all vortecs, 'hoe or crew....but for a snow beast be kinda pointless....
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2000 GMC CCSB 454/4L80 6” lift SAS 1999 Chevy CCSB 454/NV4500 6” lift 1999 GMC Yukon 350/4L60 4" SAS |
01-02-2018, 04:45 PM | #4 |
driving is in my blood
Join Date: Dec 1999
Location: Mesa AZ
Posts: 5,695
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Re: Exhaust help! 5.7 vortec plugged cats..worth paying for larger diameter replaceme
Bigger setup works fine your shop is dumb. On a totally stock 350 I doubt you'd see much from larger pipes, but long tube headers do help. Again, not really worth it for a stock winter beater in my opinion, ice and snow kinda slow things down regardless of engine output.
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-78 c10 short/step: 388cid, M20, 5/5 drop, lots more. Playtoy and first vehicle. -98 c1500 x-cab: 5.7L, 17" rims, 5/6 drop, flowmaster, helper bags,NBS rear disk brakes. -02 Suburban 4x4: leveled front -CBR600F4i, CBR600RR, CBR1000RR, and standup skis DISCLAIMER: I cant spell for the life of me. |
01-05-2018, 07:15 AM | #5 |
Registered User
Join Date: Oct 2015
Location: PNW
Posts: 3,512
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Re: Exhaust help! 5.7 vortec plugged cats..worth paying for larger diameter replaceme
Magnaflow metal matrix cat was worth the cost for me. Put it in front of a Flowmaster cat-back system. It does let a little more sound through, too.
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01-07-2018, 03:13 AM | #6 |
Senior Member
Join Date: Sep 2004
Location: Wakaw, Sask, Canada
Posts: 3,170
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Re: Exhaust help! 5.7 vortec plugged cats..worth paying for larger diameter replaceme
Thanks for the replies, all are appreciated!
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"You can take the man out of PA, but you can't take PA out of the man" |
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