Subaru OEM Short Block BRZ 2017-2020 | 10103AC840

Overview

The Genuine Subaru OEM Short Block Assembly (Part #10103AC840) is the factory-spec engine foundation for the 2017–2020 Subaru BRZ equipped with the FA20 boxer engine and 6-speed manual transmission. Engineered to exact OEM tolerances, this short block delivers the reliability and precision of a brand-new Subaru factory unit — making it the ideal solution for engine rebuilds, replacements, or high-damage repairs where rotating assembly integrity is critical.

Key Features & Benefits

• Genuine Subaru OEM Part — Built to factory specifications, ensuring exact fitment and performance matching your original BRZ drivetrain.
• Complete Short Block Assembly — Includes the engine block, crankshaft, pistons, connecting rods, and bearings — eliminating guesswork on component compatibility.
• FA20 Boxer Architecture — Subaru's horizontally opposed four-cylinder design for a lower center of gravity, improved handling balance, and the distinctive BRZ driving character.
• Factory Tolerances & Machining — Block bores, crankshaft journals, and bearing surfaces are machined to OEM spec right from the factory — no additional machining required for a stock rebuild.
• Backed by Subaru Quality Standards — As a genuine OEM assembly, this short block meets the same quality control benchmarks as the engine in a new Subaru vehicle.
• Correct for 6-Speed Manual Applications — Specifically designated for BRZ models paired with the 6-speed manual transmission, ensuring compatibility with the correct engine balancing and ancillary mounts.

What's Included

• 1x Genuine Subaru OEM Short Block Assembly (Engine Block with Rotating Assembly)
• Crankshaft, Pistons, Connecting Rods, and Main/Rod Bearings (as assembled at the factory)

Note: Cylinder head(s), valve train components, intake/exhaust manifolds, and ancillary accessories are NOT included. This is a short block only.

Specifications

Fitment & Compatibility

This Genuine Subaru short block is compatible with the following vehicles:

2017-2020 Subaru BRZ

Important: Verify your vehicle's engine code, model year, and transmission type before ordering. This short block is specifically calibrated for 6-speed manual BRZ applications. Automatic transmission variants may require a different part number.

Installation

Short block replacement is an advanced mechanical procedure requiring professional-level engine assembly experience. Installation should be performed by a qualified Subaru technician or experienced engine builder. A proper engine rebuild includes replacement of all gaskets, seals, oil pump, and coolant passages — components not included with this short block. Refer to the Subaru FA20 factory service manual for torque specifications, assembly sequences, and clearance measurements. Break-in procedures per Subaru factory guidelines should be followed upon first start-up.