LS 408 Stroker Throttle Body EFI – 600 HP on 91 Octane

 This 408ci LS stroker engine package is built for enthusiasts looking for a high-performance naturally aspirated LS engine with strong street manners, aggressive power, and modern fuel injection control. Designed to run on 91 octane pump gas, this combination produces 600 horsepower while maintaining smooth drivability, stable idle quality, and excellent throttle response.

Unlike traditional carbureted setups, this LS EFI engine package uses a Holley Terminator X Stealth 4150 EFI system for complete electronic fuel and ignition control. This includes a standalone ECU, wiring harness, and sensors, delivering reliable cold starts, self-learning AFR correction, and consistent performance across different environments and elevations.

Built around a GM OEM iron 6.0L LS block stroked to 408 cubic inches, this engine uses forged internals and AFR 238cc aluminum LS3 cylinder heads for excellent airflow, strength, and durability. A Trick Flow R-Series single plane intake manifold supports high-RPM efficiency, while a performance valvetrain system ensures stability under load.

This is a purpose-built 600 HP LS 408 stroker crate engine, designed for street performance, reliability, and repeatable real-world use.

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Order to build: Please allow 6-8 weeks

• BLOCK: GM OEM 6.0L Iron Block (Bored & Stroked) 
• CONNECTING RODS: Forged 6.125" Connecting Rods
• PISTONS: Forged Dished Pistons 
• CYLINDER HEADS: LS3 AFR 238cc
• INTAKE MANIFOLD: Trick Flow R-Series single plane
• EFI SYSTEM: Holley Terminator X Stealth 4150 EFI System (Complete Harness, Computer & Sensors) 
• COIL PACKS: High Output LS Coil Packs (Black Finish) 
• VALVE-TRAIN: LS7 Hydraulic Roller Lifters, Trunnion-Upgrade Rockers, Chromoly 5/16” Pushrods (TSP) 
• OIL SYSTEM: Melling HV oil pump
• OIL PAN: Holley GM LS Swap oil pan
• HEAD GASKETS: BTR MLS 
• FASTENERS: ARP

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When requesting a quote, you will fill out the configuration page below where you can select available options such as cosmetic finishes, accessory drive setups, and other customization requests.

Once completed, submit your configuration, and a formal quote will be provided for your LS 408 Stroker engine build.

From there, your engine will enter the production queue and begin the 6–8 week build process.