how is the cat attached to the exhaust

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Mar 6, 2009 | 11:45 AM

wgripp

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From: Valdosta, GA

Car: 1991 Trans Am GTA

Engine: L98(5.7 L TPI)

Transmission: 700r4(A4)

Axle/Gears: G80 RPO, 3:23s, Auburn Racer's Diff

how is the cat attached to the exhaust

I have dual cats on my car. Do they just bolt in via flanges between the y-pipe and the exhaust?

I'm going to replace my headers soon, and I have what I believe to be a 3inch flowmaster exhaust (not american thunder) on my car. Can I just have a piece of pipe fitted with flanges? This way I can swap it in and out for the cats as needed.

Considering there is a 3 inch exhaust already on the car, how much of a hp/torque/.25 mile time improvement should I see with shorty headers?

Thanks,
Bill

Mar 6, 2009 | 06:40 PM

Kevin91Z

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From: Orange, SoCal

Car: 1990 Pontiac Trans Am

Engine: 355 TPI siamesed runners

Transmission: Tremec T56

Axle/Gears: 12-Bolt 3.73

Re: how is the cat attached to the exhaust

They should be welded on, but its been a while since I've dealt with stock. There is a flange that connects the exhaust manifolds to the y-pipe, and then another flange that connects the y-pipe to the i-pipe.

I picked up 2.5 tenths and 2.5 MPH after installing SLP 1 5/8" headers way back when. From 14.33 @ 97.5 to 14.08 @ 100 MPH.