IAG 950 EJ25 Subaru Short Block - Subaru Models (Inc. 2002-2021 Subaru WRX / 2004-2021 STI / 2004-2013 Forester)

RACING ON SUNDAY, WORKING ON MONDAY

The IAG 950 Short Block stands as the ultimate "weekend warrior" engine block, engineered to handle up to 950 BHP, making it our toughest offering for street applications. Featuring +2mm IAG Spec H-Beam forged connecting rods, IAG-Spec JE Pistons with electroless nickel plated coating and H13 tool steel wrist pins, alongside our renowned "Fire-Lock™" head gasket system for 14mm head studs, each IAG 950 short block undergoes meticulous hand assembly using ACL or King rod and main bearings. This combination of premium components ensures that the IAG 950 Short Block is perfectly suited for both drag and road racing endeavors.

CRAFTED FROM 100% NEW COMPONENTS

The foundation of the IAG 950 Short Block begins with pristine Subaru 2.5L engine case halves. Our skilled machinists meticulously process the assembled case halves using our Haas VF-4SS CNC mill to accommodate the IAG Closed Deck inserts, effectively transforming the block into a solid deck. Following this, a set of deck plates is attached, and the short block undergoes precision boring and honing to a diameter of 99.75mm in our in-house Sunnen SV-30 computer-controlled cylinder hone. Leveraging IAG's in-house honing process, we customize piston-to-wall clearances to ensure smooth operation and minimize oil consumption. Additionally, the Haas mill precisely cuts a groove at the top of each cylinder to accommodate the Fire-Lock™ head gasket rings and drills each head bolt hole for 14mm head studs. The modified case halves are then meticulously assembled using a new 2017+ Subaru 2.5L nitride-treated STI crankshaft and IAG-Spec Tuff H-Beam connecting rods with ARP rod bolts. Every IAG Short Block is equipped with ACL or King Race rod and main bearings, meticulously balanced and blueprinted. Finally, the case halves are securely sealed using new OEM main/case bolts and sealant, completing the meticulous crafting process.

ELIMINATE CONCERNS ABOUT HEAD GASKET ISSUES

With the IAG 950 EJ25 Closed Deck Short Block, you can say goodbye to worries about head gasket failures, thanks to our exclusive "Fire-Lock™" Head gasket system. This system, validated in our race cars setting records, represents the most robust Subaru head gasket system ever created. To achieve this unmatched reliability, our engineers ingeniously separated the sealing of the combustion chamber from that of the fluid passages in the head gaskets. Our skilled machinists meticulously create a lip at the top of each cylinder to accommodate the "Fire-Lock™" ring. Once the ring is securely in place, it protrudes above the deck, ensuring a superior seal. The separate gasket bodies effectively seal oil and coolant passages, preventing them from leaking into the combustion chamber. Completing the assembly, 14mm Head studs (Not Included) securely hold everything together, providing unparalleled peace of mind.

REINFORCED WITH CLOSED DECK TECHNOLOGY

Our innovative closed deck system significantly bolsters the strength of the OEM case halves. This method provides robust support to the cylinder walls at the top of the case, effectively preventing any flexing or potential cracking near the case bolt reliefs cut into the back of the cylinder wall. Throughout the installation procedure, we utilize our Haas VF-4SS CNC mill to machine the assembled case halves, ensuring precise accommodation of the IAG Closed Deck inserts. Following this, we employ a unique process involving heating the case in an oven while simultaneously freezing the specially machined inserts with liquid nitrogen. Once heated and frozen respectively, the inserts are meticulously pressed into place and then meticulously machined to achieve a flawless mirror finish. These distinctive inserts incorporate small passages to facilitate essential coolant flow to the deck surface. Consequently, the closed deck system maintains the block's cooling efficiency and effectively prevents any risk of overheating, even during everyday driving.

ENGINEERED PISTONS BUILT FOR POWER

The pistons employed in the IAG 950 Short Blocks are meticulously tailored to endure the rigorous demands of racing. Crafted in collaboration with JE, these specialized IAG-Spec pistons boast electroless nickel plating and are constructed from 2618 Alloy. Engineered with extra thick ring lands, they are fortified to withstand high pressure without collapsing. The upgraded .250" wall H13 tool steel offset wrist pins are specifically designed to endure forces up to 950 BHP without bending or breaking. Additionally, these pistons feature JE's Perfect Skirt coating for enhanced performance and longevity.

IAG 950 Closed Deck EJ25 Short Block Includes:

• Case Halves -Converted to Closed Deck using brand new Subaru OEM case halves, bored and honed to 99.75mm.
• Fire-Lock -IAG Fire-Lock™ receiver groove machining, latest solution to prevent head gasket failure on high horsepower and high boost Subaru's - *IAG Fire-Lock™ head gaskets required
• Head Studs -Machine Case for 14mm head studs - *Head studs are sold separately
• Pistons -IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Electroless Nickel Plated Tops & Ring area, Ring Set, .250" / .906" H13 Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
• Connecting Rods -IAG-Spec Tuff H-Beam +2mm / ARP 625+ 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:

• 8.5:1 on D Cylinder Heads (EJ255)
• 8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.

Head Gasket Required:

• *IAG Fire-Lock™ .051" Head Gaskets with IAG-Spec Alloy Ring Set* PN# IAG-ENG-1740