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Forums -> C3 Fuel, Emission Control, and Exhaust Systems
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12/24/11 7:01pm - Original Message: 'Exhaust Opinion Needed'
rod7515 Lifetime Member
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Red Lion, PA - USA

1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic

Joined: 10/27/2006
Posts: 1180
Well I started the 72 today and all is good. Now for the break in I used the stack manifolds, but they will be coming off in the next day or too, and a new set of ceramic headers will be going on. Now the question is should I go with a 2 1/2" exhaust system or a 2 1/4 system. I have new flowmaster 40 series mufflers that are 2 1/2" in/out. I can use them either way as the system will be custom bent. The engine is a 383 stroker bored .040 with a .480/.490 lift hydraulic cam.
trans is a 2004r with a 3000 stall converter. I'm thinking stay with the the original thought of a 2 1/2" system but was wondering what others thought. I already replaced the original trans cross member so that wont be an issue.



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12/24/11 7:49pm - Reply: 'Re: Exhaust Opinion Needed'
Jaws79 Lifetime Member
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Sykesville, MD - USA

1979 Corvette Coupe Corvette Light Blue Midnight Blue interior Mirrored Glass T-tops

Joined: 4/27/2008
Posts: 4212
I would go with the 2.5 inch, Rod. You'll need all the flow you can with the setup you have! That's what the later models used, anyway! Get busy! Hope your Dad is doing OK.
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12/25/11 10:40am - Reply: 'Re: Exhaust Opinion Needed'
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Frederick, MD - USA

1969 convertible L71 427/435 4-speed black interior

Joined: 9/8/2003
Posts: 3398
I agree...let that baby breathe!  

Poet...Mystic...Soldier of Fortune. As always...self-absorbed, adversarial, c o c k y and in general a malcontent.

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12/25/11 12:23pm - Reply: 'Re: Exhaust Opinion Needed'
lukesvette Lifetime Member
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1979, Targa Blue (72 Color), Pace Car rear spoiler, L88 hood, Dark blue factory interior, 525HP 406, HD 700R4, 370 gears,Steeroids, composite rear spring, TT IIs wrapped in T/A Radials.

Joined: 5/18/2004
Posts: 6807
Definitely 2 1/2" Evil Smile

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12/25/11 2:58pm - Reply: 'Re: Exhaust Opinion Needed'
corvette440hp Lifetime Member
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Joined: 7/2/2006
Posts: 8205
2.5 all the way..................

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12/25/11 11:03pm - Reply: 'Re: Exhaust Opinion Needed'
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Badin Lake, NC - USA

1979 Red L-48 Corvette with Doeskin interior, 3-speed automatic, 3.55 rear; 1986 L-98 Coupe, 4+3 Manual - Satin Black and Purple (SCCA TT/Hillclimb Car); 1993 White LT-1 Coupe, Black Interior, 6-speed

Joined: 4/21/2004
Posts: 101
More flow is always better. I went with 2.5 true dual on my 79 with L48 and only mild performance upgrades. It made a nice difference over the stock 2" into 2.5

C3: 1979 Corvette Coupe, Auto, L-48, Red/Doeskin (my wife's fave);
C4s: 1986 C4 coupe (SCCA road race car), satin black, 4+3, Z51 package, L-98;  & 1993 C4 coupe, white, 6-speed, LT-1.
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12/26/11 6:23pm - Reply: 'Re: Exhaust Opinion Needed'
Norsky Lifetime Member
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Twin Lakes, CO - USA

SOLD - "The Toy" - 1970 Convertible
SOLD - "The Beast" - 1990 ZR-1 (#682)
"BLKBRRD" - 1978 Trans Am, 400ci/285hp, 4 spd, Black w/black interior, Hurst t-tops

Joined: 1/23/2002
Posts: 6727
When "The Toy" needed pipes a few years ago I went with the 2 1/2".  Kept the original exhaust manifolds though - which are 2".  Crazy part was the mufflers were 2 1/2 going in and 2" coming out.  They didn't make 2 1/2" bezels back then.

Jim Olson 

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2/2/12 10:26pm - Reply: 'Re: Exhaust Opinion Needed'
Redwingvette Lifetime Member
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Waterford, MI - USA

1973 Red coupe

Joined: 9/13/2002
Posts: 1677
Boy am I late on this one.
Anyway. I installed a Magnaflow system on my 73. It comes out of the stock manifolds at 2 1/4" and enters a X-pipe which increases the pipes to 2 1/2" all the way through to the mufflers and out the back staying at 2 1/2". 
The system is Stainless all the way.
I did have to modify the mufflers outlet to except a tip out the back of my car to match the original setup. I then purchased tips with the 2 1/2" pipes.

Brian - NCM Lifetime Member
73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
Leather seats, F-body seatbelts, Pioneer CD player
Magnaflow Exhuast System
Dewitt radiator and dual electric fans
Borgeson Steering box
Click here for Brian's Home Page 

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