LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Stock Exhaust Size

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Old Apr 15, 2010 | 12:47 PM
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Question Stock Exhaust Size

What is the inner diameter, and outer diameter on a 1995 Z28's stock exhaust.

I'm looking to put in a cutout, and I'm wondering whether 2.5" or 3.0" would be best.

Thanks!
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Old Apr 15, 2010 | 12:56 PM
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Stock exhaust is 2.75".
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Old Apr 15, 2010 | 01:23 PM
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Originally Posted by RamAir95TA
Stock exhaust is 2.75".
O.D. or I.D.?
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Old Apr 15, 2010 | 01:37 PM
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Exhaust is measured in OD
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Old Apr 15, 2010 | 03:49 PM
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Are you sure it's 2.75? I put a 3" in 2.5" out muffler on my car and the exhaust shop said the stock exhaust was 2.5 in 2.25 out. The muffler still fit fine with reducers but i bought that muffler based on the fact i had heard 2.75 in 2.5 out. they said they had to reduce it more than 1/4 inch.
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Old Apr 15, 2010 | 05:16 PM
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did research over this yesterday, stock eshaust is 2.5 inches before the cat, 2.75 inches after the cat to the muffler (that's the intermediate or "I-pipe"), and after the muffler (tail pipes) are 2.25 inch from the factory.

However,
Some SLP optioned cars had 3 inch exhaust (option on some of the Camaro SS's)

Another note, many people use the 3 inch cutouts with factory exhaust. From what I've seen, read, and heard, it works well without any issues (my car has a 3 inch cutout on it )

hope this helps
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Old Apr 15, 2010 | 06:15 PM
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Thanks for the great info guys.

Does anyone know what the OD or ID is of the 3" Flowtech cutout.

I have one on my Firebird, and for some reason I was under the impression that it was larger than 3".
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Old Apr 15, 2010 | 06:20 PM
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Originally Posted by Spd-Kilz
Thanks for the great info guys.

Does anyone know what the OD or ID is of the 3" Flowtech cutout.

I have one on my Firebird, and for some reason I was under the impression that it was larger than 3".
If its a slip on, then the IN/OUT diameters are slightly larger then 3" so it will slip over a 3" pipe. If its a weld in, then its 3" both ways.
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Old Apr 15, 2010 | 06:21 PM
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Originally Posted by whytryz28
If its a slip on, then the IN/OUT diameters are slightly larger then 3" so it will slip over a 3" pipe. If its a weld in, then its 3" both ways.
Hmmm...perhaps a slip-on 2.5" might be a good way to go?
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