SBC Tri-Y Modified 1-3/4 - 1-7/8

The Schoenfeld SBC Tri-Y Modified 1-3/4 - 1-7/8 headers are purpose-built performance exhaust components for Small Block Chevy engines competing in IMCA Modified racing and high-output street applications. These Tri-Y headers feature primary tube sizing that transitions from 1.75 inches to 1.875 inches, merged into a 3.5-inch collector designed to optimize exhaust scavenging across the RPM band typical of modified competition engines.

Constructed from mandrel-bent steel and finished in durable black paint, this pair of headers weighs 35.95 lbs and arrives with gaskets and mounting hardware included. The Tri-Y design—where primary tubes merge before the collector—improves exhaust gas velocity and reduces backpressure, translating to measurable gains in mid-range torque and peak horsepower. The graduated primary tube diameter accommodates the natural expansion of exhaust gases as they exit the engine, a critical factor in small block performance tuning where collector efficiency directly impacts combustion chamber scavenging.

These headers are engineered for IMCA-legal modified racing, where engine builders prioritize peak power delivery and consistent performance across multiple heat cycles. Street-driven modified Small Block Chevy engines also benefit from the exhaust flow improvements. Installation requires access to engine bay space typical of competition builds, and the included gasket set and hardware streamline the installation process. Buyers should verify fitment against their specific vehicle platform and header mounting configuration before purchase.

Schoenfeld has established a reputation for manufacturing headers that balance durability with measurable performance gains. When selecting headers for a Small Block Chevy racing or modified street engine, exhaust scavenging efficiency and collector design are primary technical considerations—both areas where this Tri-Y configuration delivers verified advantages over single-collector designs.