What was the largest SINGLE cat exhaust that came stock on thirdgens?
Thread Starter
Member
Joined: Jan 2001
Posts: 319
Likes: 1
From: Jacksonville, FL, USA
Car: 1988 Firebird
Engine: GM Performance Parts 350 HO
Transmission: T56
Axle/Gears: :(
What was the largest SINGLE cat exhaust that came stock on thirdgens?
Is the int. pipe 2.75"? Or is that only for cars with dual cats?
Supreme Member
Joined: Feb 2000
Posts: 1,196
Likes: 0
From: Fort Collins, Colorado
The stock cat that I just removed from my 87 IROC L98 was 3".
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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.
Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.
Best ET: 14.32 @ 97.7mph
(corrected for elevation)
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1987 Chevy Camaro IROC-Z
L98 TPI 350 (5.7L)
TH 700R-4 Transmission
Borg Warner 7.75" 9 Bolt Rear End with 2.77:1 Gears.
Current Mods: LT4 HOT Cam, Comp Cams 1.52:1 Roller Rocker Arms, Edelbrock TES 1 5/8" Headers, Catco 3" High-Flow Catalytic Converter, Hooker 3" Aerochamber Cat-Back System, Transgo Shift Kit, Performance Resource Chip, Accel Ignition, K&N Filters, JET TPI Air Foil, All Free Mods, Falken ZIEX Z-Rated Tires.
Best ET: 14.32 @ 97.7mph
(corrected for elevation)
Member
iTrader: (1)
Joined: Jul 1999
Posts: 247
Likes: 1
From: Tucson, Arizona
Car: 1987 IROC Z28
Engine: 6.0L LQ9 crate engine
Transmission: Performa Built 700R4
Axle/Gears: 3.42 10 bolt, Eaton/Moser
The 84-86 L69 HO Camaros and Birds had the Corvette cat. It was a 3-4 in. oval ported beast that bolted (4) on each end. I believe that was the largest stock cat for our cars. I had an '84 L69 HO Z28 with this cat and it was very easy to bolt in/out. I used to install a test pipe in there to "free" up the exhaust in-between smog checks!!
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Phil87IROC
Blue '87 IROC, 383 Crate Motor, KB pistons, AFR 190 heads, TPIS ZZ-9 cam, Edelbrock RPM intake, 1" TD spacer, Hooker SC/LT headers w/ Mufflex Y-pipe, Edelbrock 750 cfm Carb (#1411), Stock T-5, GM 3.42 gears w/Auburn posi.
Ohio Valley Dragstrip (KY) Trophy Bracket WINNER - 8.39 ET on a 1.82 sec. - 60'. Best MPH = 84.44. Still Tuning Carb!
Red '89 IROC L98, TES w/Flowmaster, 1LE DS, 700R4, T-Tops, K&Ns w/open air boxes, 160 T-stat, Hypertech Chip, gutted MAF & CAT, Jacobs Ign., 53kv coil, MSD wires.
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Phil87IROC
Blue '87 IROC, 383 Crate Motor, KB pistons, AFR 190 heads, TPIS ZZ-9 cam, Edelbrock RPM intake, 1" TD spacer, Hooker SC/LT headers w/ Mufflex Y-pipe, Edelbrock 750 cfm Carb (#1411), Stock T-5, GM 3.42 gears w/Auburn posi.
Ohio Valley Dragstrip (KY) Trophy Bracket WINNER - 8.39 ET on a 1.82 sec. - 60'. Best MPH = 84.44. Still Tuning Carb!
Red '89 IROC L98, TES w/Flowmaster, 1LE DS, 700R4, T-Tops, K&Ns w/open air boxes, 160 T-stat, Hypertech Chip, gutted MAF & CAT, Jacobs Ign., 53kv coil, MSD wires.
Joined: Jul 2000
Posts: 7,386
Likes: 1
From: In a mint Third Gen!
Car: Red 87 IROC-Z28 T-Top
Engine: 5.7 Tuned Port Injection
Transmission: 700R4 Auto
Axle/Gears: BW 9-Bolt 3.27
The converter was 3" but the whole system was 2 3/4". I'm not sure but kind of. 
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89 RS
Looking For:
87 IROC-Z28 350 TPI
[This message has been edited by IROCZTWENTYGR8 (edited July 03, 2001).]
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89 RS
Looking For:
87 IROC-Z28 350 TPI
[This message has been edited by IROCZTWENTYGR8 (edited July 03, 2001).]
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