S&S CYCLE T124LC Series Long Block Engine 310-0326A

The S&S Cycle T124LC Series delivers 124 cubic inches of displacement with a user-friendly 10.2:1 compression ratio—ideal for street-driven big twins that demand serious torque without sacrificing reliability across varying fuel qualities. This long block engine arrives fully assembled with S&S forged pistons, gear-drive cams, and premium Super Stock cylinder heads, allowing you to drop it into your 1999–2006 Harley-Davidson big twin and immediately integrate your existing fuel and ignition system. Whether you're upgrading a carbureted setup or pairing it with modern EFI components, the T124LC's specially machined heads accept stock-length manifolds and throttle bodies—no custom fabrication required.

The engine features cleverly redesigned cylinder head breathers positioned at stock locations, meaning your current air cleaner will bolt directly to the engine without modification. Combined with the robust T2 crankcase, high-flow oil pump, and black wrinkle powder coat finish that matches factory aesthetics, this is serious performance wrapped in a package built for real-world use.

• Displacement: 124 cubic inches
• Bore: 4-1/8"
• Stroke: 4-5/8"
• Compression ratio: 10.2:1
• Piston type: S&S forged dish (11cc)
• Camshaft: S&S 585 gear-drive Easy Start
• Crankcase: T2 design
• Oil pump: High-flow
• Cylinder heads: Super Stock (99–05 style)
• Head machining: Stock-length intake compatible
• Breather location: Stock positioning
• Fitment: 1999–2006 HD big twins (excludes 06 Dyna models)
• Installation: Long block only (no fuel/ignition included)
• Warranty: Two years
• Note: Not compatible with Softail models