Dual exhaust options for my 87 454? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jim85IROC · 01-18-2006, 09:30 AM

I've got an 87 454 1 ton 4x4 GMC that's currently got what looks like a home-made, fully welded dual exhaust with no cats. The exhaust is dieing a very quick death, so by next fall I want to replace it. I'd like to run a dual exhaust just like I have now, except that I need to try and find a place to put cats in so that I can be all nice and legal. The thing is, it's very tight up there with the exhaust running next to the transmission and transfer case above the crossmember. I don't really know if I can accomplish what I want, or if I'm going to have to try and find a y-pipe and go back to a stock type configuration.

Anybody have any info/suggestions?

1Ton · 01-18-2006, 12:31 PM

Get some aftermarket small cats and they should fit under there.

SSC's76 · 01-18-2006, 03:40 PM

http://www.maremont.com/Default.aspx?pid=7

check this site out. You may have to use 86 since your truck is the odd ball crossbreed.

Jim85IROC · 01-19-2006, 10:32 AM

I noticed that LMC has a good amount of exhaust options, but they're only 2 1/4". I've got 2.5" now, although since my truck's motor is totally stock, 2 1/4" would be sufficient. Anybody have an exhaust from LMC?

Also, does anybody have pics of the stock 454 y-pipe and catalytic converter so I can get an idea of how it's plumbed?

piecesparts · 01-19-2006, 02:18 PM

Buy a set of highflow cats and put them just down stream of the headers or exhaust manifolds, depending on wht you are running.

01-18-2006, 09:30 AM	#1
Jim85IROC Registered User Join Date: Dec 2004 Location: Readsboro, VT Posts: 502	Dual exhaust options for my 87 454? I've got an 87 454 1 ton 4x4 GMC that's currently got what looks like a home-made, fully welded dual exhaust with no cats. The exhaust is dieing a very quick death, so by next fall I want to replace it. I'd like to run a dual exhaust just like I have now, except that I need to try and find a place to put cats in so that I can be all nice and legal. The thing is, it's very tight up there with the exhaust running next to the transmission and transfer case above the crossmember. I don't really know if I can accomplish what I want, or if I'm going to have to try and find a y-pipe and go back to a stock type configuration. Anybody have any info/suggestions? __________________ 1987 GMC Sierra Classic 3500 454 TH400 My Sounddomain Page

01-18-2006, 12:31 PM	#2
1Ton Registered User Join Date: Nov 2004 Location: Jamestown NY Posts: 731	Re: Dual exhaust options for my 87 454? Get some aftermarket small cats and they should fit under there. __________________ Support your local search and rescue team.... GET LOST! Originally Posted by DURRTY if some is good more is better too much ought to be enough........

01-18-2006, 03:40 PM	#3
SSC's76 No No Join Date: Jun 2005 Location: Pueblo Colorado Posts: 1,781	Re: Dual exhaust options for my 87 454? http://www.maremont.com/Default.aspx?pid=7 check this site out. You may have to use 86 since your truck is the odd ball crossbreed. __________________ 1976 Custom Deluxe SWB Med FMB.3/4 Drop. Gen VI 454, Muncie HD 3 speed With Modified OE Hurst Shifter, 3.73 12 bolt, GMPP HO roller cam, Hooker headers, Performer intake with modified Q-jet, Accel distributor. Best 1/4 12.3 @108. Funnest run 19.84 @88 full 1/4 mile burn out. 1997 K1500 ext cab 5.7 stock except muffler

01-19-2006, 10:32 AM	#4
Jim85IROC Registered User Join Date: Dec 2004 Location: Readsboro, VT Posts: 502	Re: Dual exhaust options for my 87 454? I noticed that LMC has a good amount of exhaust options, but they're only 2 1/4". I've got 2.5" now, although since my truck's motor is totally stock, 2 1/4" would be sufficient. Anybody have an exhaust from LMC? Also, does anybody have pics of the stock 454 y-pipe and catalytic converter so I can get an idea of how it's plumbed? __________________ 1987 GMC Sierra Classic 3500 454 TH400 My Sounddomain Page

01-19-2006, 02:18 PM	#5
piecesparts Parts and more parts Join Date: Nov 2003 Location: Lebo, Kansas (middle of nowhere Posts: 6,821	Re: Dual exhaust options for my 87 454? Buy a set of highflow cats and put them just down stream of the headers or exhaust manifolds, depending on wht you are running.

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