IAG Performance 800 Series FA20 (10.5:1 Compression Ratio) Closed Deck Short Block 2013-2021 BRZ / 2013-2016 FRS / 2017-2021 GT86

The IAG 800 Short Block is designed for modified FA20 Subaru BRZs or FT86s running larger aftermarket turbochargers that require a stronger foundation to handle increased cylinder pressures. Featuring IAG Spec H-Beam forged connecting rods and a proprietary closed-deck cylinder support system, this short block strengthens the OEM FA20 cylinder walls. Head gasket sealing is enhanced with o-rings and 1/2" head studs to ensure reliability under high-pressure conditions, making it ideal for fully built bolt-on and upgraded turbo BRZs.

Each IAG 800 Short Block starts with new FA20 engine case halves, machined for improved oil flow. The case halves are assembled and machined in our Haas VF-4SS CNC mill to accept the IAG Closed Deck Inserts, which strengthen the block while maintaining coolant flow. O-ring receiver grooves and tapped holes for 1/2" head studs reduce head gasket failure. The block is bored and honed to 86.1mm on our in-house Sunnen SV-30 cylinder hone for precise piston-to-wall clearance. Assembly includes a 2020+ Subaru FA20 crankshaft, ACL or King main bearings, IAG Spec H-Beam rods with ARP2000 rod bolts, and King or ACL rod bearings. OEM bolts, sealant, and IAG Spec 86.1mm forged pistons complete the build.

Internal oil passages are inspected and optimized to ensure proper lubrication under increased loads, addressing weaknesses in the stock FA20 cases

The IAG 800 uses JE FSR 86.1mm forged pistons made from 2618 T6 Alloy. Asymmetrical skirts reduce friction and weight, while smooth dome and dish radii promote efficient flame travel. Pistons are secured with .905 x 2.250" x .210" carbon steel wrist pins and Tru Arc locks. With a 10.5:1 compression ratio, these pistons are optimized for high boost and larger turbo applications.

Includes:

• Case Halves -Brand new OEM Subaru FA20 case halves, bored and honed to 86.1mm
• Case Machining - Modified for improved oiling
• Case Machining - Bored and honed to 86.1mm
• O-Ringing - Machine and O-Ring Deck Surface
• Head Studs - Machine Case for 1/2" head studs - *Head studs are sold separately
• Pistons -IAG-Spec 86.1mm Forged Pistons, Ring Set, and .210" x 2.250" Chromoly Wrist Pins. 10.5:1 Compression
• Connecting Rods -IAG-Spec H-Beam / ARP2000 Rod Bolts
• Rod -ACL or King XPG
• Main Bearings -OEM or King XPG
• Crankshaft -New Subaru FA20 crankshaft
• Case / Main Bolts -Standard Subaru case bolts
• Hardware - OEM Oil Plug - comes preinstalled at the oil pan location

Note: Compression Ratio: 10.5:1 compression on standard gasket thickness.