IAG 950 2.35L Destroked Long Block Engine w/ IAG 950 Heads for 02-14 WRX, 04-21 STI, 04-13 FXT, 05-09 LGT

Part Details:

The IAG 950 2.35L Destroked Long Block Engine with IAG 950 Cylinder Heads is a race-engineered, high-RPM-focused engine package built for Subaru EJ platforms targeting extreme power with improved responsiveness. Rated for builds targeting up to 950 BHP, this long block combines a 2.35L destroked closed-deck IAG 950 short block with CNC-ported IAG 950 cylinder heads and a reinforced valvetrain to support big-turbo and motorsport applications.

A destroked configuration is commonly chosen for high-RPM performance and spool characteristics. By pairing a 2.0L crankshaft with the EJ platform, this long block is optimized for rapid spool, improved rod ratio, and increased durability under sustained high engine speeds.

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 high-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 the 2.35L destroked 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 950 BHP
• Final power capability depends on turbo system, fueling, cooling, and tuning quality
• Professional installation is strongly recommended
• ECU tuning is required

IAG 950 2.35L Destroked Short Block

• Brand-new Subaru OEM case halves
• IAG Fire-Lock™ receiver groove machining (Fire-Lock™ head gaskets required)
• Machined for 14mm head studs (head studs sold separately for the short block)
• JE 99.75mm FSR 2618 custom pistons
• 0.240″ H13 tool steel wrist pins
• JE ProSeal ring set
• Custom IAG-spec +2mm H-beam forged connecting rods with ARP 625+ rod bolts
• ACL race rod and main bearings
• 2.0L FHI crankshaft (destroked configuration)
• OEM Subaru case and main bolts

Compression Ratio

All compression ratios are calculated using IAG Fire-Lock™ head gaskets:

• 9.2:1 – EJ255 (D heads)
• 8.8:1 – EJ257 (B, V, W heads)

IAG 950 CNC Ported Cylinder Heads

• Brand-new Subaru OEM WRX STI cylinder head castings
• IAG CNC ported intake and exhaust runners
• GSC 37mm (+1mm) intake valves
• GSC 33mm (+1mm) SuperAlloy exhaust valves
• IAG-spec beehive valve springs and retainers
• GSC manganese valve guides
• GSC valve stem seals
• Kelford DLC coated lifter buckets
• GSC Stage 2 billet camshafts
• Multi-angle valve job
• Machined cam lobe clearance
• Drilled for 14mm head studs
• Resurfacing, ultrasonic cleaning, and final lash set

Gaskets, Hardware & Accessories

• IAG / ARP 14mm head stud set
• IAG Fire-Lock™ 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 and competitive motorsport EJ builds
• Supporting modifications (fuel system, turbo system, cooling, oiling) should match power goals
• Fire-Lock™ head gasket requirements should be followed for proper sealing
• 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