Hooker 4 inch Universal Sidemounts reduce backpressure, improving low end torque for better performance and fuel economy.The classic Hooker 4 into 1 (NOTE: 3 tubes are dummies) collectors utilize huge 2-1/8" diameter primaries mandrel bent to maintain a consistent inside diameter for maximum flow. Their 4" 16 gauge sidepipes utilize long lasting slip-in mufflers. These mufflers are easily removed for racing purposes. The sidemounts have a show quality chrome finish. Mufflers are sold separately.