1000 Series FA20 Closed Deck Short Block

The IAG Performance 1000 Series FA20 Closed Deck Short Block is a robust engine foundation designed for 2015-2021 Subaru WRX models seeking extreme power and durability. It is engineered to support up to 1000 brake horsepower, making it suitable for high-boost applications, street cars, drag racers, and track weapons that demand reliable performance under significant cylinder pressure. At its core, this short block features a precision-machined closed deck conversion that reinforces the factory FA20 engine case halves. IAG's process combines advanced CNC machining with cryogenically cooled inserts to create a mechanically locked structure that resists cylinder wall movement and cracking, while maintaining proper coolant flow for optimal thermal management. The assembly is fully balanced and blueprinted, incorporating IAG-spec JE forged 2618 alloy pistons with Electroless Nickel Plating, IAG-spec H-beam forged connecting rods with ARP 625+ rod bolts, and a new Subaru FA20 crankshaft. Premium ACL or King rod and main bearings are utilized for enhanced reliability. The design also includes provisions for the proprietary IAG Fire-Lock head gasket system and 14mm head studs, ensuring a secure combustion seal under extreme conditions. Installation of the IAG 1000 FA20 Closed Deck Short Block is recommended for professional engine builders or experienced enthusiasts due to its complexity. It requires precise torque application and is compatible with the IAG Fire-Lock head gasket system and 14mm head studs, which are sold separately. Proper tuning is essential for safe operation and to maximize the engine's power potential and longevity. Verify fitment for your specific 2015-2021 WRX model and engine condition, as additional machining or overboring may be necessary if the block or cylinder head has been previously modified.