Modified Header SBC Tri-Y 23 Deg

The Modified Header SBC Tri-Y 23 Deg by BEYEA CUSTOM HEADERS is a purpose-built exhaust manifold engineered for small-block Chevrolet (SBC) engines seeking maximum performance gains. This tri-Y design is the choice for serious enthusiasts and engine builders who demand superior scavenging efficiency and horsepower increases over factory cast-iron alternatives. Whether you're building a street rod, performance cruiser, or track-focused engine, this header delivers the exhaust velocity and flow characteristics needed to unlock your engine's full potential.

The tri-Y collector design with a 23-degree merge angle is optimized for SBC cylinder head porting patterns, ensuring balanced exhaust scavenging across all eight cylinders and reducing backpressure losses. The 23-degree geometry promotes optimal gas velocity and pressure wave timing, allowing cylinders to expel combustion gases more completely during the exhaust stroke. This forces fresh fuel charge deeper into the cylinder on the intake cycle, resulting in measurable torque and horsepower improvements across the RPM band. The mandrel-bent tubing construction minimizes turbulence compared to welded alternatives, further enhancing flow efficiency and engine responsiveness.

This modified header is ideal for SBC applications ranging from 283 to 400 cubic-inch displacement engines, making it versatile for both period-correct restorations and modern high-performance builds. Installation requires basic mechanical skills and standard hand tools; fitment is direct to factory SBC cylinder head bolt locations. Pair this header with a quality exhaust system and proper tuning to maximize gains; many builders see 15–25 horsepower increases depending on overall engine setup and breathing modifications. Ensure clearance verification in your specific engine bay before purchase, as tight installations may require heat shielding or minor chassis modifications.