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Exaust pipes holding it back?

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Old Oct 11, 2006 | 10:31 PM
  #1  
85T/A350's Avatar
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Car: 1987 Pontiac Trans Am
Engine: 350 Vortec
Transmission: 700R4
Axle/Gears: 3.42
Exaust pipes holding it back?

I have true dual 2 in pipes on my 85 Trans Am which has a 350.I was wondering if 2 in duals hold it back a whole lot.
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Old Oct 12, 2006 | 11:49 AM
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fin170703's Avatar
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From: england, UK
Car: '87 iroc camaro
Engine: 350 L98
Transmission: 700-R4
Axle/Gears: 3.27 posi
editted due to not wanting to give out the wrong info

Last edited by fin170703; Oct 15, 2006 at 01:48 AM. Reason: wrong info posted
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Old Oct 12, 2006 | 11:58 AM
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ezysk's Avatar
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From: South East Michigan
Car: 1986 Firebird / 1985 Trans-Am
Engine: 305 4BBL / 383 4BBL++
Transmission: 700R4 / 700R4
Axle/Gears: ?.?? / 3.47
What are you running BTW.
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Old Oct 12, 2006 | 07:27 PM
  #4  
85T/A350's Avatar
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Car: 1987 Pontiac Trans Am
Engine: 350 Vortec
Transmission: 700R4
Axle/Gears: 3.42
Its a 350 bored .40 over with an Edelbrock Performer Carb,Edelbrock Performer EPS intake,Hooker shorty headers and 305 heads
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Old Oct 13, 2006 | 12:08 PM
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Fullsizewagon's Avatar
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From: Oslo, Norway
Engine: '85 Monte SS L69 305
Transmission: TH 200-4R
Axle/Gears: 3.23
My guess is you'll be fine up to 5000 rpm. If you get the opportunity sometime you can opt for up to 2-1/2" to really free it up.
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Old Oct 14, 2006 | 05:34 PM
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83 Crossfire TA's Avatar
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Well, that’s about the same cross section as the stock, 2.75” single and would flow a little less… so if your 350 is healthy enough that the stock exhaust would be a restriction then your 2” twins are a restriction also.
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Old Oct 14, 2006 | 06:14 PM
  #7  
fin170703's Avatar
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From: england, UK
Car: '87 iroc camaro
Engine: 350 L98
Transmission: 700-R4
Axle/Gears: 3.27 posi
that suprises me , i'm certainly not arguing the point , even if its a 2" exhaust serving each bank of 4 cylinders?
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Old Oct 14, 2006 | 07:32 PM
  #8  
Airpak's Avatar
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From: Edmonton, AB, Canada
Car: 1982 Camaro Z28
Engine: 350
Transmission: Auto
Axle/Gears: 10 bolt auburn posi 3.73
This has been posted many times. Dual 2" is way too small. Should be atleast 2.5" if your going dual.

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Old Oct 15, 2006 | 12:14 AM
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From: Hamilton
Car: 1990 IROCZ Camaro
Engine: 350 4bbl, 200cc Heads, 270hr Cam
Transmission: 700R4 w/ Trans-Go shift kit.
Axle/Gears: GM 10 bolt Posi
I would think that 2" is too small.
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Old Oct 15, 2006 | 02:54 AM
  #10  
BlkBird408's Avatar
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From: KC. KS
Car: 89 Firebird
Engine: 408
Transmission: 700r4
Axle/Gears: 12 bolt/4.11
Yeah I agree. I think 2" is to small. Going with at least a 2.5" will free up some power. 3" would be even better!
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Old Oct 15, 2006 | 03:15 AM
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83 Crossfire TA's Avatar
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fin170703, not picking on you, everyone makes a mistake sometime and admitting/accepting that is a big thing, but in the future it makes more sense to just leave the post up because sometimes it disappearing can lead to more confusion then having incorrect info corrected further down.

That chart posted is about appropriate for something like a flowmaster muffler, but you don’t have to go quite that large with something freer flowing like a dynomax ultraflow or a magnaflow.
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Old Oct 15, 2006 | 11:35 AM
  #12  
fin170703's Avatar
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From: england, UK
Car: '87 iroc camaro
Engine: 350 L98
Transmission: 700-R4
Axle/Gears: 3.27 posi
Fair point crossfire.

i should have researched a bit more before posting the wrong info , my exhaust guy told me that if i wanted to go true duals 2" would be plenty, i in turn took it as gospel.

turns out he does not have the capabilities to bend anything over 2" .
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Old Oct 15, 2006 | 02:34 PM
  #13  
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so of course, 2" is enough...


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Old Oct 15, 2006 | 03:33 PM
  #14  
fin170703's Avatar
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From: england, UK
Car: '87 iroc camaro
Engine: 350 L98
Transmission: 700-R4
Axle/Gears: 3.27 posi
Yep


you live and learn
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