IAG 950 EJ25 2.5L Subaru Short Block - 950 BHP

IAG 950 EJ25 Subaru Closed Deck Short Block for 02-14 WRX, 04-21 STI, 05-09 LGT, 04-13 FXT

RACE ON SUNDAY, WORK ON MONDAY

The IAG 950 Short Block is the ultimate "weekend racer" block. Built to withstand up to 950 BHP, this is our strongest "Street" short block offering. The IAG 950 short block features +2mm IAG Spec H-Beam forged connecting rods, IAG-Spec JE Pistons with electroless nickel plated coating with H13 tool steel wrist pins, and our venerable "Fire-Lock™" head gasket system for 14mm head studs. Each IAG 950 short block is hand assembled using ACL or King rod and main bearings. This combination of parts makes the IAG 950 the perfect block for drag or road racing. :contentReference[oaicite:0]{index=0}

BUILT WITH 100% NEW COMPONENTS

The IAG 950 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 Haas mill also cuts a groove at the top of each cylinder to accept the Fire-Lock™ head gasket rings and drills each head bolt hole for 14mm head studs. 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. :contentReference[oaicite:1]{index=1}

NEVER WORRY ABOUT HEAD GASKET FAILURES

The IAG 950 EJ25 Closed Deck Short Block features our proprietary "Fire-Lock™" Head Gasket system. This system has been proven in our record setting race cars to be the strongest Subaru head gasket system ever produced. To achieve these results our engineers separated the combustion chamber sealing from the fluid sealing aspects of the head gaskets. Our machinists carefully machine a lip at the top of each cylinder to accept the "Fire-Lock™" ring. With the ring locked in place, it stands proud above the deck, providing a superior seal. The separate gasket bodies take care of sealing oil and coolant passages and keeping them out of the combustion chamber. 14mm Head studs (Not Included) hold the assembly together. :contentReference[oaicite:2]{index=2}

CLOSED DECK FOR EXTRA STRENGTH

Our unique closed deck system significantly increases the strength of the OEM case halves. This process supports the cylinder walls at the top of the case in order to prevent flexing and possible cracking where the case bolt reliefs are cut into the back of the cylinder wall. During the installation process we machine the assembled case halves in our Haas VF-4SS CNC mill to accept the IAG Closed Deck inserts. Once the case has been machined we heat it in an oven while freezing the specially machined inserts with liquid nitrogen. The inserts are then pressed into place and then machined to a mirror finish. The unique inserts feature small passages that allow needed coolant flow to the deck surface. This means that the closed deck system does not affect the block's cooling ability and will not cause overheating, even in daily drivers. :contentReference[oaicite:3]{index=3}

PISTONS SPECIALLY DESIGNED WITH POWER IN MIND

The pistons used in the IAG 950 Short Blocks are specifically designed to support the rigors of racing. Designed in partnership with JE, these IAG-Spec pistons feature electroless nickel plating and a 2618 Alloy. Extra thick ring lands resist collapsing under pressure. The upgraded .250" wall H13 tool steel offset wrist pins are designed to hold up to 950 BHP without bending or breaking. The pistons also feature JE’s Perfect Skirt coating. :contentReference[oaicite:4]{index=4}

IAG 950 CLOSED DECK SHORT BLOCK INCLUDES

What's Inside:

• 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 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 with 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:

• 9.1:1 on D Cylinder Heads (EJ255)
• 8.8:1 on B, V and W EJ257 Heads with IAG Fire-Lock™ head gaskets

Power Rating:

Power: The IAG 950 Short Block has a power output rating of 950 BHP

Please Note: This item is not eligible for standard ground shipping and must be delivered via freight. 
STOCK NOTICE: This item is built to order and carries a minimum 6-8 week build time.

IMPORTANT DELIVERY NOTE: Your order is shipping Via Truck Freight which requires you to be available at the time of receipt. There is a possibility the trucking company will try to schedule a delivery time with you. At the time of delivery, the driver will hand you the delivery receipt also referred to as the bill of lading, you will use this to notate any damages to the shipment. It is important that you fully inspect the shipment from all sides and notate any dents, punctures or rips in the outside packaging on the delivery receipt. Once you've inspected your shipment from the outside, you will need to open it and check the product in its entirety for damages and notate them if any. If there is no damage sign for the package and enjoy! In the rare case, you do find that your order arrived with damages, it is important you follow these steps. - Do not refuse the product- Document the damages in as much detail as possible on the Bill of Lading
- Take numerous photos from all angles (including packaging)
- Keep the product and contact the shipping company to start the damage claim
- Contact us either by phone or email for the next steps In the situation where the delivery driver is unable to wait for you to open and inspect your product, simply document "driver was unable to wait for inspection." All damage must be noted on the Bill of Lading before signing and initiating a damage claim. If the damage is not notated before signing for the item it is assumed to be in good condition. This will forfeit the ability for a shipping claim and you will not be eligible for refund or replacement.