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85T/A 305/QJ work in progress.

 

A cat-back is everything in the exhaust system behind the catalytic converter(s). This includes the intermediate pipe, the over-axle pipe, the muffler and the outlets (tailpipes). You can exploit this area by using a larger diameter intermediate pipe (usually 2 1/2 or 3 inch) and/or a high-flow muffler. There are tons of companies to choose from. If you want the best and have the money, get Borla. If you are on a budget, get Dynomax. There are also companies in between like Flowmaster and SLP that make really nice systems.

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'83 Firebird 2.8
'89 Firebird Formula 350
2nd owner, red/grey, t-tops, dual cats, and a 3.27:1 rear
K&N, TB bypass, No MAF screens, CAI, full Accel ignition

 

Ahhhh, I get it. I take it you should have a high flow cat to go along with it.

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85T/A 305/QJ work in progress.

 

Yes.

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Looking For:

87 IROC-Z 350 TPI
84 TRANS AM 305 H.O.