SS-XR EJ25 Short Block - Build a 1000HP Subaru Engine

Built and assembled in-house, this short block represents years of development and testing. Engineered for strength, consistency, and long-term reliability, it forms the foundation for high-boost, high-RPM builds rated up to 1,000+ HP.

Key Features

Pistons

• JE Ultra Forged Pistons

  • 2618 Alloy

  • 8.5:1 Compression Ratio

  • Upgraded .210” wall wrist pins

  • Lateral gas ports

  • Ceramic crown coating

  • Skirt coating for reduced friction

Connecting Rods

• I-Beam +2mm Longer Rods for improved rod ratio

• Equipped with ARP CA625 hardware

Bearings

• High-Performance Coated Main Bearings

• Custom Fi Performance Rod Bearings

Crankshaft

• Billet 79mm crankshaft

• Pinned main journals - Line honed

• ARP Case Hardware

Case

• OEM Subaru 2.5L Case Halves

• V4 Closed-Deck Conversion

  • Machined grooves for high-boost head gaskets

• Used, seasoned, and precision machined

Assembly

• Professionally blueprinted and assembled at FI Performance

• Machined to support 1/2” head studs

Power & Application

• Rated for 1,000+ HP

• Designed for high-boost, high-RPM race applications

• Safe for up to 9,500 RPM with proper supporting components

• Engineered for extreme strength, consistency, and long-term durability

Required Supporting Components

• Fire Ring Head Gaskets – Must order through FI Performance

• High-performance cylinder heads

• Upgraded head studs

• Properly matched fuel system and valvetrain components

Oil System Recommendations

• For builds up to 8,200 RPM, must use FI Performance modified racing ported oil pump or IAG stage 2

• For builds over 8,200 RPM, dry sump oiling system highly recommended

• Ensures proper lubrication and maximum engine longevity under extreme conditions