Flowmaster American Thunder Trans X-Member Back Exhaust System Height: 17.250 Width: 15.000 Length: 52.500 Weight: 66.8 Fitment: 1968/Pontiac/Firebird/Base/6.6L 6555CC 400Cu. In. V8 GAS OHV Naturally Aspirated::Convertibles Require Aftermarket X-Brace Or 3/8 in. Shims For Clearance, Not Legal For Sale Or Use In California^^1968/Pontiac/Firebird/Base/6.6L 400Cu. In. V8 GAS Naturally Aspirated::Convertibles Require Aftermarket X-Brace Or 3/8 in. Shims For Clearance, Not Legal For Sale Or Use In California^^1968/Pontiac/Firebird/Base/5.7L 5733CC 350Cu. In. V8 GAS OHV Naturally Aspirated::Convertibles Require Aftermarket X-Brace Or 3/8 in. Shims For Clearance, Not Legal For Sale Or Use In California^^1968/Pontiac/Firebird/Base/5.7L 350Cu. In. V8 GAS Naturally Aspirated::Convertibles Require Aftermarket X-Brace Or 3/8 in. Shims For Clearance, Not Legal For Sale Or Use In California^^1968/Pontiac/...