went under and messured my pipe at the muffler and its only 2 1/4 OD.is this factory or was it changed to a v6 one or something?
Kevin91Z
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Mar 23, 2026
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- Car1990 Pontiac Trans Am
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Yes that's factory for the single cat TPI cars in '89-'92, its the same as the TBI engines, not V6. The dual cat TPI cars got the bigger exhaust.