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Vehicle Fitment:

EJ25 2.5L - WRX, STI, LGT, FXT


Power: The IAG 750 Short Block has a power output rating of 750 BHP

IAG 750 EJ25 Subaru Closed Deck Short Block For WRX, STI, LGT, FXT - 750BHP

PriceFrom $4,999.99
  • The IAG 750 Short Block is designed to solve the majority of common problems which plague modified EJ25 engines, especially at higher horsepower levels. The IAG 750 short block builds off our IAG 550 block's strengths by adding our proprietary closed deck system. This system strengthens and supports the cylinder walls to prevent cracks which can occur with increased cylinder pressures. (This is the most common issue when increasing horsepower.) The IAG 750 also features 99.75mm JE Forged Pistons and IAG Spec H beam connecting rods, along with ACL or King Race bearings. These components also significantly strengthen the common failure points such as cracked ring lands and spun bearings.

    The IAG 750 Short Block starts with brand new Subaru 2.5L engine case halves. Our machinists machine the assembled case halves in our Haas VF-4SS CNC mill to accept the IAG Closed Deck inserts, transforming the block into a solid deck. Next, a deck pair of deck plates are attached and the short block is bored and honed to 99.75mm in our in-house Sunnen SV-30 computer controlled cylinder hone. IAG's in-house honing process allows us to set custom piston to wall clearances to ensure quiet operation and reduced oil consumption. The modified case halves are then assembled using a new 2017+ Subaru 2.5L nitride treated STI crankshaft and IAG-Spec Tuff H-Beam connecting rods with ARP rod bolts. IAG Short blocks feature ACL or King Race rod and main bearings and are all balanced and blueprinted. Finally, the case halves are sealed with new OEM main/case bolts and sealant.


  • IAG 750 Closed Deck Includes:

    • Case Halves - Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm.
    • Pistons - IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Ring Set, .210" 9310 Steel Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
    • Connecting Rods - IAG-Spec Tuff H-Beam / ARP2000 Rod Bolts.
    • Rod / Main Bearings - ACL or King Race bearings.
    • Crankshaft - Standard New Subaru Nitride Treated 2017+ STI Crankshaft.
    • Case / Main Bolts - Standard FHI Subaru case bolts.

    Compression Ratio:

    • 9.5:1 on D Cylinder EJ255 Heads w/ OEM Head Gasket
    • 8.9:1 on B, V and W EJ257 Heads w/ OEM Head Gasket
    • 9.6:1 on S20 Heads without Combustion Chamber Mod and with OEM Head Gasket
    • 9.1:1 on D Cylinder EJ255 Heads w/ .039" JE Proseal Head Gasket
    • 8.6:1 on B, V and W EJ257 Heads w/ .039" JE Proseal Head Gasket
    • 9.2:1 on S20 Heads without Combustion Chamber Mod and with .039" JE Proseal Head Gasket
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