Wehrli Custom Fabrication WCF100412-SC High Flow Cast Aluminum Turbo Intake Horn

The Wehrli Custom Fabrication WCF100412 High Flow Turbo Intake Horn is a precision-engineered cast aluminum upgrade designed to replace the restrictive OEM plastic inlet on 6.6L LBZ and LMM Duramax engines. With a 4.8-inch inlet diameter — the largest intake horn available for this application — it delivers a 20% improvement in airflow over stock, translating directly into improved turbo response, enhanced throttle feel, and better overall engine efficiency.

Constructed from CNC machined cast aluminum, this intake horn is built for durability and precision fitment. It eliminates the factory resonator connection for a cleaner engine bay appearance and a more aggressive turbo and engine sound. A built-in PCV port maintains proper crankcase ventilation, while the O-ring turbo seal ensures a leak-free connection. The kit includes a silicone reducer boot and stainless steel T-bolt clamps for a complete, secure installation. Finished in a custom powder coat, this horn is Made in the USA.

Key Features:

• 4.8-inch inlet — largest intake horn available for LBZ/LMM applications
• 20% airflow improvement over the restrictive factory plastic inlet
• CNC machined cast aluminum construction for strength and precision
• Includes PCV port for factory crankcase ventilation retention
• Eliminates factory resonator for improved appearance and sound
• Includes silicone reducer boot, stainless steel T-bolt clamps, and O-ring seal
• Custom powder coat finish
• Made in the USA
• Supersedes part number WCF100341
• Replaces GM OEM part number 98011738

Compatibility Note: Not compatible with OEM or aftermarket intakes (such as K&N) that do not use a silicone boot connection at the horn. The intake pipe used must accept a 4-inch boot and clamp for proper fitment.