Stock 454 exhaust system size? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

383Ram · 06-01-2009, 06:39 AM

I am looking for the exhaust size for the pipes that would have came on a stock 454 truck. I am assuming it was a single pipe setup rather than duals, but am unsure. I just wanted to have something for reference, and the Walker OE catalog doesnt show anything for a big block.

team39763 · 06-02-2009, 09:46 PM

On Summitracing.com, I found a direct fit cat converter that says 2.5" for 75-79 C10 with 454. So I assume that was the stock size.

**78 Big10 454** · 06-02-2009, 09:52 PM

383Ram, my 454 exhaust is 2.5 inches factory stock. 1978 C-10.

**truckfan** · 06-03-2009, 06:13 AM

my 1977 c-10 454 has factory duals w/ no cats and no "unleaded fuel only" decal on the fuel gauge. i think the factory size is 2 1/2

383Ram · 06-03-2009, 06:22 AM

I assume all these systems are single--except for the last post? I am trying to get a feel for what the factory used as to what i want to do with my system. I know the factory tried to comprimise on power and quietness, which is what i want to also. I am just having a hard time believing that a 3" single system (which is on the truck now) will be adequate for a 454 that is going in. I may have to scrap it and start over.

Keith Seymore · 06-03-2009, 11:41 AM

Quote:

Originally Posted by truckfan

my 1977 c-10 454 has factory duals w/ no cats and no "unleaded fuel only" decal on the fuel gauge. i think the factory size is 2 1/2

Any idea why that might be? I recall our '75 C10 350 was a single exhaust with a cat (because - back in "the day" - we blew the cat up, scattering the pellets all over the roadway).

Was your truck built in Oshawa or had some other emissions package?

K

**Captkaos** · 06-03-2009, 12:30 PM

If the 454 was heavy half'd the cats wouldn't be required in some states....

**78 Big10 454** · 06-03-2009, 08:27 PM

From the factory, I had pipes coming off the exhaust manifolds into one Cat then branching off to two mufflers and tailpipes. I modified it by running a dedicated Cat and muffler on each side. Although technically illegal by California standards, I've never been caught at the biennial smog tests. In short, both systems were 2.5 inch.

06-01-2009, 06:39 AM	#1
383Ram Registered User Join Date: Apr 2009 Location: Truckville, The Capital of NY Posts: 217	Stock 454 exhaust system size? I am looking for the exhaust size for the pipes that would have came on a stock 454 truck. I am assuming it was a single pipe setup rather than duals, but am unsure. I just wanted to have something for reference, and the Walker OE catalog doesnt show anything for a big block.

06-02-2009, 09:46 PM	#2
team39763 Registered User Join Date: Feb 2007 Location: Texas Posts: 469	Re: Stock 454 exhaust system size? On Summitracing.com, I found a direct fit cat converter that says 2.5" for 75-79 C10 with 454. So I assume that was the stock size. __________________ 1982 Silverado - SBE, cleaned up GM heads, small cam, TH350, 850 Demon, 4.56 gears, and caltracs. Best time so far 11.8@XXXMPH Last edited by team39763; 06-02-2009 at 09:46 PM.

06-02-2009, 09:52 PM	#3
78 Big10 454 78 Big10 454 Join Date: Jul 2008 Location: Pismo Beach, CA Posts: 839	Re: Stock 454 exhaust system size? 383Ram, my 454 exhaust is 2.5 inches factory stock. 1978 C-10.

06-03-2009, 06:13 AM	#4
truckfan Senior Member Join Date: Apr 2009 Location: Lawrence KS Posts: 821	Re: Stock 454 exhaust system size? my 1977 c-10 454 has factory duals w/ no cats and no "unleaded fuel only" decal on the fuel gauge. i think the factory size is 2 1/2 __________________ 1981 Chevy C30 440 Holmes 42K one owner miles

06-03-2009, 06:22 AM	#5
383Ram Registered User Join Date: Apr 2009 Location: Truckville, The Capital of NY Posts: 217	Re: Stock 454 exhaust system size? I assume all these systems are single--except for the last post? I am trying to get a feel for what the factory used as to what i want to do with my system. I know the factory tried to comprimise on power and quietness, which is what i want to also. I am just having a hard time believing that a 3" single system (which is on the truck now) will be adequate for a 454 that is going in. I may have to scrap it and start over.

06-03-2009, 12:30 PM	#7
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Re: Stock 454 exhaust system size? If the 454 was heavy half'd the cats wouldn't be required in some states.... __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

06-03-2009, 08:27 PM	#8
78 Big10 454 78 Big10 454 Join Date: Jul 2008 Location: Pismo Beach, CA Posts: 839	Re: Stock 454 exhaust system size? From the factory, I had pipes coming off the exhaust manifolds into one Cat then branching off to two mufflers and tailpipes. I modified it by running a dedicated Cat and muffler on each side. Although technically illegal by California standards, I've never been caught at the biennial smog tests. In short, both systems were 2.5 inch.



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