Description:The exhaust manifolds found in the 1966-1996 Small Block Chevy engines were designed to combine the exhaust gasses from each of the cylinders quickly with a manifold that was cost effective to produce. Our 4-1 Block Hugger off-road headers are designed to allow the exhaust gasses to flow more freely from each cylinder bank and combine in a more efficient manner. Block Hugger style headers are meant to be used where space for long tube headers isn't available due to steering and cross member clearance issues. Tubing has been optimized for the 5.0L(305ci), 5.3L(327ci), 5.7L(350ci), and 6.6L(400ci) engines. This creates a reduction in cylinder backpressure and improved exhaust gas velocity. These improvements free up lost horsepower and torque. An added benefit is a more performance oriented exhaust sound.Package: --1 x Header Exhaust System--Hardware as Shown in the Picture aboveNote:--Professional Installation is Highly Recommended (No Instruction and Wiring Diagram Included)

• Made with 1 5/8" OD diameter heavy duty mandrel bent 18 gauge tubing
• Large 2 1/2" collectors. Reducers are 2 "
• 4 1/4" length from the bottom edge of the head to the outside of the middle tubes
• Made with thick 5/16" flanges to resist warpage
• Works best with straight plug heads,BUT will not work with angle plugs

Made with 1 5/8" OD diameter heavy duty mandrel bent 18 gauge tubingDEMOTOR