SP Concepts Works Edition Big Bore Exhaust for 2018-2026 Harley Softail

Product Description

SP Concepts Big Bore 4.5 Works Edition Exhaust for 2018-2026 Harley M8 Softail

Take your Milwaukee-Eight Softail build to the next level with the SP Concepts Big Bore 4.5 Works Edition Exhaust. Combining the high-flow performance of SPC's Big Bore 4.5 system with individually pie-cut, hand-welded stainless steel headers, the Works Edition delivers an unmistakable custom appearance while retaining the airflow, torque and horsepower capability required for serious performance builds.

The defining feature of the Works Edition is its handcrafted header construction. Each section of stainless steel tubing is precisely pie cut and TIG welded back together by hand at the SP Concepts facility in Lake Elsinore, California. The result is a highly detailed exhaust system with a race-inspired appearance that showcases the fabrication work rather than hiding it behind traditional smooth-bend tubing.

Performance comes from a large 4.5" rolled-cone muffler with a stepped internal baffle that transitions from 2-1/4" to 2-1/2". This high-flow design is engineered to improve bottom-to-midrange torque and horsepower while providing the exhaust capacity needed for large-displacement Milwaukee-Eight engines. SP Concepts states that, when properly tuned, the system can support engines ranging from 88" through 143".

The headers are constructed from heavy-duty .065" stainless steel and step from 1-3/4" to 1-7/8" and then to 2" at the collector. This stepped design helps maintain exhaust velocity while providing increased flow as engine demand rises, making the Big Bore 4.5 Works Edition suitable for everything from mildly modified street bikes to serious big-bore performance builds.

Each system features machined stainless steel header collars, 18mm O2 sensor bungs and included 12mm adapters for compatibility with factory oxygen sensors or applicable wideband and autotune systems. A complete mounting hardware kit is also included.

Choose from Stainless, Black ONYX or Platinum finishes. A Low Rider ST-specific configuration is available to ensure proper fitment on FXLRST applications.

Fitment

Fits most 2018-2026 Harley-Davidson Milwaukee-Eight Softail models.

Compatible Models: Fits applicable Street Bob, Low Rider, Low Rider S, Low Rider ST, Sport Glide, Softail Standard, Heritage Classic, Softail Slim and other compatible M8 Softail models within the listed year range.

2026 Models: Designed to fit the updated 2026 Harley-Davidson Softail platform, including Low Rider ST models with the updated cam cover configuration.

Does Not Fit: Harley-Davidson Breakout or Fat Boy models.

Note: Verify your exact motorcycle model, year, engine combination and exhaust configuration before ordering. Proper tuning is recommended when installing a performance exhaust, particularly on modified or large-displacement engines.

Features

• Premium Works Edition performance exhaust for Harley-Davidson Milwaukee-Eight Softail models
• Fits most 2018-2026 M8 Softail applications
• Fits updated 2026 Softail and Low Rider ST models
• Does not fit Breakout or Fat Boy models
• Headers are individually pie cut and TIG welded back together by hand
• Handcrafted at the SP Concepts facility in Lake Elsinore, California
• Distinctive race-inspired Works Edition appearance
• 4.5" high-flow rolled-cone muffler
• Stepped internal baffle transitions from 2-1/4" to 2-1/2"
• Designed to improve bottom-to-midrange torque and horsepower
• Can support 88" through 143" engines when properly tuned
• .065" stainless steel header construction
• Stepped headers transition from 1-3/4" to 1-7/8" to 2" at the collector
• Hand TIG welded from top to bottom
• Machined stainless steel header collars
• 18mm O2 sensor bungs
• Includes 12mm O2 sensor adapters
• Compatible with stock O2 sensors or applicable autotune/wideband sensors
• Complete mounting hardware kit included
• Available in Stainless, Black ONYX and Platinum finishes
• SP Concepts Part Number: SPC-1-003-WE-ST