IAG Performance IAG 1150 2.5L Subaru Closed Deck High Compression Short Block - 1150 BHP

Built for high-octane fuels such as E85 and race gas, the IAG 1150 High Compression 2.5L Closed Deck Short Block is the ideal choice for high-horsepower drag racing scenarios. While suitable for street use, it’s built to dominate the track. Compared to our regular 1150 Short Block pistons with compression ratios of 8.5:1 (D Heads, EJ255) and 8.2:1 (B, V, and W Heads, EJ257), the IAG High Compression 1150 steps it up to 9.9:1 on D Heads and 9.5:1 on B, V, and W Heads, unlocking more power and efficiency needed for race applications. This high compression Subaru block includes additional features to further strengthen the OEM case halves including Stage 4 Closed Decking and pinned mains secured with ARP case hardware. Our record-setting "Fire-Lock" Head Gasket system and 14mm head studs are used to ensure a tight seal even in extreme conditions. In addition, this short block also features IAG Spec "Tri-Beam" +2mm forged connecting rods. An IAG Spec Billet Crankshaft is used to support additional oiling and prevent main bearing distortion. The upgraded block, billet crank, connecting rods, race bearings, and forged pistons are able to support additional engine load produced by the largest turbochargers and the most demanding uses including competition drag racing. The IAG 1150 High Compression Short Block includes all the premium components of our 1150 short block, upgraded with custom high compression pistons. These pistons increase the compression ratio by reducing the pistons negative cc volume, and changing from a “dish” to a “flat top” style piston, making them ideal for racing applications where power and efficiency matter most. To ensure optimal performance, this short block requires consistent use of high-octane fuels like E85 or race gas. Pump gas is suitable only during the break-in process.