S&S Cycle V124 Evolution Long Block Engine for 1984-1999 Harley-Davidson Evo Big Twin

S&S Cycle V124 Evolution Long Block Engine for 1984-1999 Harley-Davidson Evo Big Twin

The V124 is the largest displacement S&S engine that still fits in a stock Evolution Big Twin frame — and it does it without asking you to modify anything. Drop it into your Softail, FXR, Dyna, or Touring chassis, bolt up the carb you already own, and ride out with 128 horsepower and 133 ft-lb of torque where your stock 80-inch used to be. This is the engine the Evo platform was always capable of being.

Key Features

• 124 cubic inch displacement — the largest S&S engine that fits a stock Evolution Big Twin frame without modification
• Shorter than stock engine height eliminates clearance concerns in tight stock and custom frames
• S&S performance cylinder heads with forged rocker arms and high-lift valve springs — assembled and ready to run
• Head-style case breathing for improved airflow and engine efficiency
• Specially machined cylinder heads retain compatibility with stock-length intake manifolds — no manifold swap required
• EFI compatible — crank and case machined for crank position sensor; use with aftermarket module or add-on tuner for fuel injection applications
• S&S 640 gear-driven camshaft
• S&S forged pistons with piston cooling jets for sustained high-output durability
• 3-piece flywheel assembly for strength and serviceability
• High-Volume High-Pressure (HVHP) oil pump for reliable lubrication under all conditions
• Electronic compression releases for easier starting
• Available in three finish options — Natural, Black (wrinkle black), and Black Edition (gloss black)
• Does not include carburetor or ignition — use your existing carb (re-jetting required) or aftermarket ignition system
• 2-year warranty; made in the USA

Technical Specifications

• Displacement: 124 cubic inches
• Bore: 4-1/8″
• Stroke: 4-5/8″
• Compression Ratio: 10.8:1
• Horsepower (approx.): 128 HP
• Torque (approx.): 133 ft-lb
• Camshaft: S&S 640 gear-driven
• Pistons: S&S forged with piston cooling jets
• Flywheel Assembly: 3-piece; 1.671″ diameter crankpin
• Wristpin Diameter: .927″
• Oil Pump: High-Volume High-Pressure (HVHP)
• Breathing: Head-style case breathing
• EFI Compatibility: Yes — crank and case machined for crank position sensor
• Natural Finish: Natural cast aluminum with chrome covers
• Black Finish: Wrinkle black with chrome rocker covers
• Black Edition Finish: Gloss black covers throughout
• Induction/Ignition: Not included
• Warranty: 2 years
• Country of Origin: USA

Fitment Notes

• Designed for 1984-1999 carbureted Harley-Davidson Evolution Big Twin chassis — Softail, FXR, Dyna, and Touring platforms
• FXR fitment extends to 2000 (final FXR production year)
• Compatible with 1970-1999 custom chassis designed for alternator-style Evolution primary
• Carburetor and ignition are NOT included — existing carb can be reused with re-jetting; aftermarket performance ignition required
• If running EFI: crank position sensor interface is machined into the case — aftermarket module or add-on tuner required for calibration
• Stock-length intake manifolds are retained — no manifold replacement needed
• A high-performance clutch is recommended due to the significant torque increase over stock
• Engines are shipped without oil — fill before first start
• Not legal for sale or use in California on any pollution-controlled motor vehicle
• Not legal for sale or use on any EPA pollution-controlled motor vehicle
• Review the Fitment tab for a complete year and model breakdown before purchasing