IAG 1000 FA24 Subaru Closed Deck Short Block for 2022-24 WRX – 1000 BHP

Part Details:

The IAG 1000 FA24 Closed Deck Short Block is a high-strength, precision-built engine foundation developed specifically for the 2022–2024 Subaru WRX equipped with the FA24 engine. Designed for enthusiasts targeting major power increases, this short block combines IAG’s CNC-machined closed-deck conversion with forged internals to deliver exceptional durability under high boost.

Rated for builds targeting up to 1,000 BHP, the IAG 1000 FA24 is intended for big-turbo street cars, track-focused builds, and drag racing applications where cylinder stability, head gasket sealing, and long-term reliability are critical.

Closed Deck & Fire-Lock Design

At the core of the IAG 1000 FA24 is a closed-deck conversion performed on brand-new Subaru OEM FA24 case halves. This reinforcement dramatically improves cylinder wall support, reducing distortion under high cylinder pressure and making the block far more capable of handling elevated boost levels than the factory open-deck configuration.

To further enhance sealing at extreme power levels, the block features IAG Fire-Lock™ receiver groove machining. This system is designed to work with IAG Fire-Lock™ head gaskets to reduce the risk of head gasket failure in high-boost FA24 applications.

Engine Internals & Construction

The IAG 1000 FA24 short block is assembled using forged and performance-grade components selected to withstand high RPM and extreme cylinder pressure. It features IAG-spec JE FSR forged pistons measuring 94.25mm, manufactured from 2618 alloy with electroless nickel-plated crowns and ring lands for improved heat resistance and durability.

IAG-spec +2mm H-beam forged connecting rods with ARP 625+ rod bolts provide increased strength over factory components, while ACL performance rod and main bearings support consistent oil clearances under demanding conditions. The rotating assembly is completed with a heat-treated OEM Subaru FA24 crankshaft.

Reliability & Performance Benefits

High-boost FA24 builds place significant stress on the factory engine architecture. The IAG 1000 FA24 addresses these limitations by combining closed-deck cylinder support, Fire-Lock sealing technology, and forged internals designed specifically for high-output applications.

This short block is engineered for builders who want to push the FA24 platform far beyond stock limits while maintaining the reliability required for aggressive street use and motorsport environments.

Vehicle Fitment Overview

This short block is designed for the Subaru WRX equipped with the FA24 engine. Full year-by-year compatibility is listed in the Vehicle Fitment tab above.

This is a performance short block, not a stock replacement. Vehicle configuration, supporting modifications, and build goals should always be verified prior to purchase.

What’s Included

• Brand-new Subaru OEM FA24 case halves
• IAG CNC-machined closed-deck conversion
• IAG Fire-Lock™ receiver groove machining (Fire-Lock™ head gaskets required)
• Machined for 14mm head studs
• IAG-spec JE FSR 94.25mm 2618 forged pistons with electroless nickel-plated crowns and ring lands
• JE ProSeal ring set
• 0.230″ wall / 0.866″ diameter H13 wrist pins with clips and skirt coating
• IAG-spec +2mm H-beam forged connecting rods with ARP 625+ rod bolts
• ACL performance rod and main bearings
• Heat-treated OEM Subaru FA24 crankshaft
• OEM Subaru case and main bolts

Compression Ratio

• Calculated compression ratio with Fire-Lock head gaskets: 10.5:1

Required Components

• IAG Fire-Lock™ 0.051″ head gaskets with IAG-spec alloy ring set (PN: IAG-ENG-1760)
• 14mm head studs (required)

Installation & Build Notes

• Professional installation is strongly recommended
• ECU tuning is required
• Supporting modifications (fuel system, turbo system, cooling, oiling) are necessary for high-power operation
• High compression and boost levels require careful tuning and proper fuel selection
• Final power capability depends on the complete engine build and tuning strategy

Recommended Supporting Upgrades

• 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

Learn more about IAG Performance engine and reliability solutions