Crossover Headers 1-3/4

The Schoenfeld Crossover Headers 1-3/4 (model 136H) is a pair of conventional crossover headers engineered for Small Block Chevy engines seeking improved exhaust scavenging and performance gains. These headers feature a 1.75-inch primary tube diameter that merges into a 3.5-inch collector, a proven combination for naturally aspirated street and moderate performance applications where peak horsepower occurs in the mid-range rpm band.

Constructed from steel and finished in black paint, these crossover headers are supplied complete with gaskets and mounting hardware, eliminating the need for separate fastener sourcing during installation. The 1.75-inch primary sizing balances back-pressure management with flow characteristics suited to stock-displacement and mildly modified Small Block engines, while the crossover design promotes more uniform exhaust gas evacuation across cylinders compared to traditional log-style manifolds. Total weight is 28.9 lbs for the pair.

These headers are designed for builders restoring or upgrading Small Block Chevy powerplants in street rods, muscle cars, and classic performance vehicles. Crossover headers are favored where conventional side-exit headers present clearance conflicts or where a central collector exit simplifies exhaust plumbing. The 1-3/4 primary diameter represents the sweet spot for carbureted and fuel-injected naturally aspirated engines in the 350–400 cubic-inch range, delivering measurable torque improvements without aggressive scavenging penalties at cruise rpm.

Schoenfeld has built a reputation for straightforward, functional exhaust components that prioritize durability and tuning flexibility. Installation requires proper header gaskets and careful bolt torque sequencing to prevent leaks; the included gaskets and hardware package accelerates the installation process. Verify collector exit routing and ground clearance before purchasing to ensure fitment within your specific chassis and exhaust system configuration.