S&S Cycle Engine Long Block

S&S Cycle Engine Long Blocks: American-Built Power for Harley-Davidson Big Twins

When a stock motor reaches the end of its service life — or simply can't keep pace with the riding you demand — an engine long block from S&S Cycle represents one of the most trusted paths to more displacement, more torque, and a truly transformed motorcycle. S&S Cycle has been engineering high-performance V-twin powerplants in Viola, Wisconsin, for decades, and their long block lineup is a showcase of that accumulated expertise: precision-machined, dyno-validated, and built entirely in the USA.

Two Distinct Long Block Families: V-Series and T-Series

S&S Cycle organizes its long block offerings around two core engine families, each designed to slot into a specific generation of Harley-Davidson platform.

• V-Series Long Blocks — Built for Evolution Big Twin chassis from 1984–1999, the V-Series covers displacements from the classic V80 (80 ci) all the way up to the hard-hitting V111 (111 ci) and the stroker V124 (124 ci). The V111 and V124 benefit from the addition of head-style case breathing, making them an economical path to upgrade an Evo-powered bike. The V124 is rated at 128 hp and 133 ft-lb of torque , making it a serious performer for custom builds and service replacements alike. All S&S V-Series engines include a 2-year warranty.
• T-Series Long Blocks — Engineered for 1999–2017 Harley-Davidson Twin Cam Dyna and Touring platforms, the T-Series spans from the street-friendly T111 to the chassis-maxing T143. The S&S T143 Long Block is the largest S&S engine that will fit in a stock Harley-Davidson chassis , displacing a full 143 cubic inches.

What Sets S&S Long Blocks Apart

S&S doesn't just bore out a stock cases and call it done. Every long block is assembled with purpose-built S&S components throughout. The T-Series engines feature CNC-machined S&S B3 cylinder heads with two-bolt exhaust flanges, S&S 635 easy-start gear-drive cams, and 1.725:1 rocker arms delivering a total lift of .674 inches for increased horsepower and torque. The assembly is housed in S&S Super Stock™ T2 crankcases with reed breather valve three-piece flywheels, complemented by a high-flow oil pump and cam cover.

On the V-Series side, the V111 long block delivers a 30% increase in HP and torque over stock, uses a short stroke for less vibration and longer engine life, and features a high-volume, high-pressure (HVHP) oil pump along with durable S&S 3-piece flywheels and performance 585 cam and valve springs.

Bolt-In Fitment, Carb-Ready Simplicity

One of the most practical advantages of the S&S long block format is what it doesn't include. Fuel and ignition systems are intentionally omitted, so riders can carry over their existing carburetor, air cleaner, or EFI throttle body. The T111, T124, and T124LC Long Block engines bolt directly into a stock touring chassis with no modifications, and if a rider has already added a performance carburetor or EFI throttle body and tuner, they can use it on the new engine. Specially machined cylinder heads allow use of stock-length manifolds, and the crank and case are machined for a crank position sensor, making the engine EFI compatible.

Finish Options to Match Your Build

S&S Cycle understands that aesthetics matter as much as performance on a custom build. Long blocks are offered in a range of finishes — Natural, Wrinkle Black, Chrome with Wrinkle Black, and the popular Black Edition, which swaps chrome engine covers for gloss black billet pieces for a blacked-out look. Every configuration is made in the USA, reflecting S&S Cycle's long-standing commitment to domestic manufacturing quality.

Whether you're rebuilding a tired Evo, chasing big-inch Twin Cam power, or constructing a ground-up custom, browse the full selection of S&S Cycle Engine Long Blocks to find the displacement and finish that fits your vision.