IAG Performance 750 Closed Deck EJ25 Long Block w/ IAG 750 Heads 2002-2014 WRX / 2004-2021 STI / 2004-2013 Forester XT / 2005-2009 Legacy GT

The IAG Performance Hand-Built Subaru EJ25 Closed Deck Long Block Engine Packages are complete, valve cover to valve cover crate engines, offering a true “drop-in” solution for WRX, STI, Forester XT, and Legacy GT. These engines combine proven IAG 750 Closed Deck Short Block and IAG 750 Cylinder Head packages with race-proven components for a fully assembled, ready-to-install engine.

Designed to support up to 750 BHP, the IAG 750 Short Block starts with a brand new EJ25 Subaru case converted to closed deck and bored and honed to 99.75mm. Internals include IAG-Spec JE FSR 2618 forged pistons, .210" 9310 wrist pins, IAG-Spec Tuff H-Beam connecting rods with ARP 2000 bolts, and an OEM STI crankshaft. ACL or King Race bearings are used, and the assembly is fully balanced and blueprinted. The proprietary closed deck system strengthens the cylinder walls to prevent flexing and cracks, while maintaining proper coolant flow for reliability, even in daily-driven vehicles.

Each IAG 750 Short Block features JE FSR forged pistons with an asymmetrical skirt design, reducing weight and friction while maintaining strength. The pistons are secured with thick .210" wrist pins and Tru Arc locks to handle increased boost and cylinder pressures.

The IAG 750 CNC Pocket Ported Competition Cylinder Heads are designed for weekend racers and track duty, supporting up to 750 BHP. Starting with new OEM Subaru castings, the heads are CNC pocket ported to improve intake and exhaust flow while preserving spool. Decks are resurfaced, valve seats are cut with a multi-angle job, and heads are ultrasonically cleaned. Reassembly includes GSC standard size valves, GSC Viton valve stem seals, IAG Stage 1 valve springs with titanium retainers, and OEM keepers. GSC S1 camshafts and OEM lifter buckets are installed for added performance.

Pocket porting enlarges and blends the area beneath the valve seat, a critical airflow region, while leaving the remainder of the port unchanged to maintain velocity at high power levels. GSC S1 camshafts provide increased power and torque across the RPM range without sacrificing low-end performance, making them ideal for upgraded turbos or higher horsepower builds. All cams come with new OEM lifter buckets and are set to proper valve lash.

Whats Inside:

IAG 750 EJ25 2.5L Closed Deck Short Block:

• 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.

IAG 750 CNC Pocket Ported Cylinder Heads:

• Heads - Brand New Subaru OEM WRX STI Cylinder Head Castings
• Machine Porting - CNC Pocket Ported
• Intake Valves - GSC 36mm Intake Valves
• Exhaust Valves - GSC 32mm Exhaust Valves
• Springs / Retainers - GSC Single Valve Springs & Titanium Retainers
• Guides - OEM Valve Guides
• Valve Seals - GSC Valve Stem Seals
• Lifters - OEM Lifter Buckets
• Camshafts - GSC Stage 1 Billet Camshafts
• Multi-Angle Valve Job
• Machined Cam Lobe Clearance
• Resurface
• Ultrasonic Cleaning
• Final Lash

Gaskets, Hardware & Accessories:

• Head Studs - ARP 625+ 11mm Set
• Head Gaskets - OEM
• Valve Cover Gaskets - OEM
• Cam Seals - OEM
• Valve Covers - OEM
• Wrist Pin Seal, Rear Main Seal & Separator Kit
• Crankshaft Woodruff Key