IAG 750 Closed Deck Long Block Engine w/ IAG 750 Heads for 02-14 WRX, 04-21 STI, 04-13 FXT, 05-09 LGT

Part Details:

The IAG 750 Closed Deck Long Block Engine with IAG 750 Cylinder Heads is a fully assembled, high-performance engine package built for Subaru EJ platforms targeting serious power levels. Designed to support builds up to 750 BHP, this long block combines IAG’s closed deck 750 short block with CNC pocket-ported IAG 750 cylinder heads to deliver exceptional durability, airflow, and high-RPM stability.

This engine package is well suited for big-turbo street builds, E85 applications, and motorsport use where cylinder strength, valvetrain reliability, and consistent power delivery are critical.

Vehicle Fitment Overview

Designed for Subaru EJ-series platforms including WRX, STI, Forester XT, and Legacy GT models. Full year-by-year compatibility is listed in the Vehicle Fitment tab above.

This is a performance long block, not a stock replacement. Vehicle configuration, emissions requirements, and overall build goals should always be verified prior to purchase.

What This Long Block Includes

This is a complete long block assembly that includes a closed deck short block, fully assembled CNC-ported cylinder heads, and the gaskets and hardware listed below.

Important Notes: What’s Not Included

• Intake manifold
• Turbocharger and turbo system components
• Fuel injectors and fuel system components
• Accessory components (alternator, A/C compressor, etc.)
• ECU calibration (tuning)

Power & Build Expectations

• Rated for builds targeting up to 750 BHP
• Final power capability depends on turbo system, fueling, cooling, and tuning quality
• Professional installation is strongly recommended
• ECU tuning is required

IAG 750 Closed Deck Short Block Options

EJ25 2.5L Closed Deck Short Block

• Brand-new Subaru OEM EJ25 case halves converted to closed deck
• Bored and honed to 99.75mm
• IAG-spec JE FSR 99.75mm 2618 forged pistons with ring set
• 0.210″ 9310 steel wrist pins with skirt coating and offset wrist pins
• IAG-spec Tuff H-beam connecting rods with ARP2000 rod bolts
• ACL or King race rod and main bearings
• New Subaru nitride-treated STI crankshaft (2017+)
• OEM Subaru case and main bolts

EJ20 2.0L Closed Deck Short Block

• Brand-new Subaru OEM EJ20 case halves converted to closed deck
• Bored and honed to 92.5mm
• IAG-spec JE FSR 92.5mm 2618 forged pistons with ring set
• 0.210″ 9310 steel wrist pins with skirt coating and offset wrist pins
• IAG-spec H-beam connecting rods with ARP2000 rod bolts
• ACL or King race rod and main bearings
• New Subaru WRX 2.0L crankshaft with improved oil passages
• OEM Subaru case and main bolts

IAG 750 CNC Pocket-Ported Cylinder Heads

• Brand-new Subaru OEM WRX STI cylinder head castings
• CNC pocket porting for improved airflow
• GSC 36mm intake valves
• GSC 32mm exhaust valves
• GSC single valve springs with titanium retainers
• OEM valve guides
• GSC valve stem seals
• OEM lifter buckets
• GSC Stage 1 billet camshafts
• Multi-angle valve job
• Machined cam lobe clearance
• Resurfacing, ultrasonic cleaning, and final lash set

Gaskets, Hardware & Accessories

• ARP 625+ 11mm head stud set
• OEM head gaskets
• OEM valve cover gaskets
• OEM cam seals
• OEM valve covers
• Wrist pin seal, rear main seal, and separator kit
• Crankshaft woodruff key

Installation & Build Notes

• Designed for big-turbo, E85, and motorsport-oriented builds
• Supporting modifications (fuel system, turbo system, cooling, oiling) should match power goals
• Break-in procedures and oil selection should follow engine builder recommendations
• Final results depend on the complete setup and professional tuning

Recommended Supporting Upgrades

• Air / Oil Separator (AOS) – helps reduce oil vapor ingestion and protect the intake system
• Oil pickup and baffle upgrades – improves oil control and reduces bearing failure risk
• Long block installation kits – simplifies installation with required gaskets and hardware
• Engine installation fluid kits – includes break-in oil and coolant for first startup

Performance Airflow Upgrades

• Corsa Veloce Stradale Rear-Facing Intake Manifold– increases airflow and supports high-horsepower EJ engine builds

Learn more about IAG Performance engine and reliability solutions