IAG Performance 750 EJ25 Closed Deck Short Block

Subaru WRX/STI/FXT/LGT (EJ25)

The IAG Performance 750 EJ25 Closed Deck Short Block delivers race-proven reliability for high-performance Subaru builds targeting 750+ BHP. Featuring IAG's proprietary closed deck design and premium forged internals, this short block provides the foundation for serious street and track applications where durability under boost is essential.

1 in Stock – Almost Gone

What's Included

IAG 750 Closed Deck Includes:

• Case Halves: Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm
• Pistons: IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Ring Set, .210" 9310 Steel Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
• Connecting Rods: IAG-Spec Tuff H-Beam / ARP2000 Rod Bolts
• Rod / Main Bearings: ACL or King Race bearings
• Crankshaft: Standard New Subaru Nitride Treated 2017+ STI Crankshaft
• Case / Main Bolts: Standard FHI Subaru case bolts

Compression Ratio

• 9.5:1 on D Cylinder EJ255 Heads w/ OEM Head Gasket
• 8.9:1 on B, V and W EJ257 Heads w/ OEM Head Gasket
• 9.6:1 on S20 Heads without Combustion Chamber Mod and with OEM Head Gasket
• 9.1:1 on D Cylinder EJ255 Heads w/ .039" JE Proseal Head Gasket
• 8.6:1 on B, V and W EJ257 Heads w/ .039" JE Proseal Head Gasket
• 9.2:1 on S20 Heads without Combustion Chamber Mod and with .039" JE Proseal Head Gasket

Key Features

• Closed Deck Block Design: Superior cylinder wall support for high-boost applications
• Power Capacity: Designed to support 750+ BHP (560+ kW)
• IAG Fire-Lock Technology: Proprietary receiver groove machining prevents head gasket failure
• Precision Machined: CNC-machined closed deck conversion with exact tolerances
• Forged Internals: High-strength forged pistons and connecting rods
• Performance Bearings: ACL or King Race Series bearings throughout
• Quality Assurance: Each engine individually tested and inspected

Technical Specifications

• Displacement: 2.5L (EJ25)
• Block: IAG Closed Deck Block with Fire-Lock receiver groove machining
• Bore: 99.75mm (bored and honed)
• Pistons: IAG-Spec JE FSR 99.75mm 2618 forged pistons with perfect skirt coating
• Rods: IAG-Spec Tuff H-beam connecting rods with ARP2000 rod bolts
• Crankshaft: Nitride treated Subaru 2017+ STI crankshaft
• Bearings: ACL or King Race Series main and rod bearings

Fitment

• Subaru WRX (2002-2014)
• Subaru STI (1993-2021)
• Subaru Legacy GT (2005-2012)
• Subaru Forester XT (2004-2013)

Required Components (Sold Separately)

• Cylinder heads
• Timing components
• Oil pump and water pump
• All gaskets and seals

Why Choose IAG Performance?

IAG Performance has earned its reputation as one of the most trusted names in Subaru performance engineering. With decades of motorsport experience and countless championship-winning builds, their closed deck short blocks represent the gold standard for high-horsepower Subaru applications. Each engine is hand-assembled by experienced technicians and undergoes rigorous quality control to ensure it meets IAG's exacting standards.

Installation Notes

Professional installation is strongly recommended. This short block requires additional components including cylinder heads, IAG Gaskets, head studs, timing components, oil pump, water pump, and all associated gaskets and seals. Custom tuning is mandatory for proper operation and to achieve rated power levels.