Free shipping* Performance Guaranteed online support
CALL US 201.935.2910
IAG Performance Stage 4 TUFF EJ25 Closed Deck Shortblock

IAG Performance Stage 4 TUFF EJ25 Closed Deck Shortblock

IAG Performance/Willall Racing Stage X EJ25 Billet Aluminum Shortblock

IAG Performance/Willall Racing Stage X EJ25 Billet Aluminum Shortblock

IAG Performance Stage 4 Extreme EJ25 Closed Deck Shortblock

IAG Stage 4 Extreme EJ25 Closed Deck
$7,499.99
In stock
SKU
IAG-ENG-1453

IAG Stage 4 Extreme Closed Deck EJ25 Subaru Short Block

The IAG Stage 4 Extreme Short Block starts with brand new Subaru 2.5L EJ25 engine case halves. The case halves are split and the main webs are CNC machined in our Haas VF-4SS CNC mill for 9.5mm pins to reduce distortion and movement of the case in extreme conditions. The case halves are then reassembled and IAG machines the case to accept the IAG CLOSED Deck Inserts that transform the block into a solid deck. The unique inserts feature small passages that allow needed coolant flow to the deck surface. The case halves are then CNC machined for our new Fire-Lock head gasket solution that is loosely derived from diesel technology where a counterbore step is machined around each cylinder bore allowing specially sized fire rings to drop into the machined area and head gasket bores. The Stage 4 Extreme case is CNC drilled and tapped to fit 14mm head studs. Utilizing the new Fire-Lock gasket solution along with larger IAG / ARP 14mm head studs, nuts, and washers reduce the chances of the heads lifting under extreme boost conditions. The short block is then Deck Plate bored and honed to 99.75mm in our in-house Sunnen SV-30 the most advanced automotive cylinder hone available. IAG‘s in-house honing process is able to set custom piston to wall clearances to best fit your needs. The modified case halves are then assembled using a Manley Billet crankshaft that is matched to ACL or King race main bearings. Custom IAG TRI-BEAM +2mm connecting rods by Manley and ARP 625+ rod bolts are utilized along with ACL or King race rod bearings. The case halves are sealed with OEM sealant and ARP main bolts. IAG-Spec 99.75mm Custom Forged Pistons with .250" / .927" wrist pins with electroless nickel plated tops and ring area are chosen to finish the Stage 4 Extreme short block. IAG‘s custom pistons feature a lightweight design while increasing strength where you need it and are designed to work exclusively with the IAG +2mm Tri-Beam connecting rods. The wrist pin is short and is made from strong H13 tool steel. The pin piers are profiled to increase pin boss strut. Finally, IAG‘s pistons feature a 25% larger oil ring for reduced oil consumption and added gas ports that aid ring sealing in high boost conditions. 

Stage 4 Extreme Closed Deck Includes:

  • Case Halves - Converted to Closed Deck from brand new OEM Subaru case halves, bored and honed to 99.75mm.
  • Pinned Mains - Machine case for 9.5mm pinned mains and lined honed.
  • 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 - Machined for 14mm Head Studs.
  • Pistons - IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Electroless Nickel Plated Tops & Ring area, Ring Set, .250" / .927" H13 Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
  • Connecting Rods - IAG-Spec Tri-Beam Connecting Rods with ARP 625+ Rod Bolts.
  • Rod / Main Bearings - ACL or King Race Bearings.
  • Crank - Manley Billet Turbo Tuff Crankshaft.
  • Case / Main Bolts - ARP Main Bolts.



Additional Options Available:

  • Head Studs - IAG / ARP Spec 14mm head studs, nuts, and washers - $550
  • Head Gaskets - IAG Fire-Lock .051" Head Gaskets with IAG-Spec Alloy Ring Set* Required for use with this short block -$249.99
  • Oil Pump - Subaru JDM 12mm High Volume Oil Pump - $219, or 11mm Subaru Oil Pump - $199.95
  • IAG Oil Pickup - Upgraded oil pickup featuring heavy gauge steel tubing, 2 point bracket & mesh filter - $129.99
  • Hardware / Seal Option - $105.99 (Includes: Wrist pin plugs, washers, separator cover, bolts, etc. In case you don’t want to transfer from the original engine).


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


    Power: The IAG Stage 4 Extreme Short Block has a power output rating of 1100BHP.

    *All IAG short blocks are balanced and blueprinted. 

    Hardware / Seal Option:


    Not planning on reusing your original short block service plugs and covers? IAG offers a simple comprehensive cover and seal kit that includes (1) Rear main seal, (3) OEM wrist pin plugs, (3) OEM wrist pin plug washers, (1) OEM separator cover, (6) OEM separator cover bolts, (1) OEM wrist pin service cover, (1) OEM wrist pin service cover O-ring and (2) OEM wrist pin service cover screws. *If you are reusing your original wrist pin service plugs and covers always replace the (3) OEM wrist pin plug washers and (1) wrist pin service cover O-ring before installing a short block to avoid potential leaks. *Never reuse a rear main seal on a new short block.

    IAG SHORT BLOCK WARRANTY INFORMATION, TERMS & CONDITIONS
    IAG Performance is confident in our products and services and we proudly stand behind our workmanship. Therefore, we offer a limited warranty against defects in workmanship or materials, covering both parts and labor, for a standard period of 1-Year/12,000-Miles or an enhanced warranty of 2-Years/24,000-Miles if installed by an IAG Certified Engine Installer.

    IAG (Standard) Short Block Warranty Limitations are as follows:

      • Standard Warranty period begins on the day the engine was delivered.

      • Standard Warranty applies only to short block components manufactured and assembled by IAG Performance.

      • Standard Warranty does not extend to any other part of the engine, turbocharger, accessories, or vehicle in which the engine is installed, or subsequent damage to any component or part of the vehicle due to an engine failure.

      • Standard Warranty coverage excludes any shipping costs incurred to return the product to our facility. If the warranty claim is denied, the client will be responsible for return shipping from our facility.

      • Standard Warranty coverage excludes any and all labor expenses needed for reassembly, as well as any components (i.e. gaskets, fluids, etc.) required for reinstallation.

      • Standard Warranty is only offered if the short block is professionally installed, with receipts provided.

      • Standard Warranty is non-transferrable and only offered to the original purchaser of the engine.

      • All parts used in the assembly of the IAG built short block carry the manufacturer’s individual component warranties. No warranty is expressed or implied for any customer-supplied components.

      • Standard Warranty clients are responsible for initiating a warranty claim with IAG directly.

      • The client agrees that they will be held responsible for all engine tear down costs for claims deemed insufficient and/or invalid.

      • Proof of proper maintenance is the owner’s responsibility.

      • Any covered repairs or replacement will not extend the warranty period.

      • You must register your engine by completing the online form at https://www.iagperformance.com/warranty




    IAG Certified Engine Installer (Enhanced) Warranty Limitations are as follows:

      • The Enhanced Warranty Program is only available for engines sold and installed after 5-1-2019. Engines purchased and installed prior to 5-1-2019 will still qualify for the Standard Engine Warranty Program

      • Enhanced Warranty period begins on the day the vehicle is completed and delivered to the client by the IAG Certified Engine Installer (as evidenced by client receipts.)

      • The installer must register the engine by completing the online form at https://www.iagperformance.com/warranty

      • Enhanced Warranty applies only to short block components manufactured and assembled by IAG Performance.

      • Enhanced Warranty does not extend to any other part of the engine, turbocharger, accessories, or vehicle in which the engine is installed, or subsequent damage to any component or part of the vehicle due to an engine failure.

      • Enhanced Warranty coverage excludes any shipping costs incurred to return the product to our facility. If the warranty claim is denied, the client will be responsible for return shipping from our facility.

      • Enhanced Warranty coverage includes limited labor expenses needed for reassembly, as well as any gaskets required for reinstallation.

      • Enhanced Warranty is only offered if the short block is professionally installed by an IAG Certified Engine Installer, with receipts provided.

      • Enhanced Warranty is non-transferrable and only offered to the original purchaser of the engine.

      • All parts used in the assembly of the IAG built short block carry the manufacturer’s individual component warranties. No warranty is expressed or implied for any customer-supplied components.

      • Enhanced Warranty claims must be initiated by an IAG Certified Engine Installer ONLY.

      • The client agrees that they will be held responsible for all engine tear down costs for claims deemed insufficient and/or invalid.

      • Proof of proper maintenance is the owner’s responsibility.

      • Any covered repairs or replacement will not extend the warranty period.




    IAG Short Block Warranty does NOT cover:

      • Damage due to improper engine installation, negligence, abuse, alteration or accident.

      • Improper or insufficient engine break-in (failure to follow assigned break-in procedure, including oil changes.)

      • Damage resulting from improper engine tuning including, piston skirt scuffing, damage indicated by head gaskets exhibiting burned or crushed fire ring(s), or damage caused by improper combustion, detonation, pre-ignition or extreme cylinder pressures, as indicated by melted, broken, or eroded pistons or bent wrist pins/worn wrist pin bushings.

      • Damage resulting from improper transmission installation or clutch adjustment, including crankshaft thrust bearing damage on transmission side only.

      • Damage caused by lack of proper maintenance, failure to follow scheduled maintenance intervals or failure to use or maintain proper type and levels of fluids, fuel, oil, and lubricants, including accelerated wear from contaminated oil or fuel wash.

      • Damage caused by the failure of other engine related components, such as fuel injectors or pump, wiring, water pump, oil pump, sensors, or gaskets.

      • Damage related failure to replace contaminated oiling components. Oiling components may include oil pump, oil cooler, oil pick up, oil pan, oil-driven AVCS cam gears, screened banjo bolts and all other contaminated oiling related components depending on the model year and layout of the vehicle.
      • Engine damage without documentation of professional installation, including proof of purchase of replacement oiling components. Proof of proper maintenance is the owner’s responsibility.

      • Damage due to abuse, including over-rev, overheating, lean conditions or oil starvation.

      • Engines where the odometer has been disconnected or mileage has been altered.

      • Failure caused by short block or cylinder head casting flaw or failure.

      • Damage caused by vehicle collisions or other accidental damage, including shipping damage.

      • Damage caused by foreign objects dropped or drawn into cylinders or the crankcase, including water or other fluids.

      • Towing, shipping, rental vehicles, loss of time, inconvenience, loss of use or other economic loss to the extent allowed by law.

      • Damage to subsequent components, such as a turbocharger or wastegate, due to failure of an engine or engine component.




    Standard Warranty Claim Procedure
    All Standard Warranty claims must be directed to IAG Performance for assignment of a return merchandise authorization number (RMA). Following the issuance of an RMA claim number, IAG requires the engine to be returned to our facility for inspection and final determination of claim eligibility. The client is responsible for all shipping and handling costs to return the engine back to IAG. Upon receipt of the engine, IAG will disassemble the engine to determine if product manufacturing, assembly, parts defect, improper installation, or improper tuning directly or indirectly caused the engine to prematurely fail. After engine teardown is complete IAG will determine whether warranty coverage applies.


    Enhanced Warranty Claim Procedure
    All Enhanced Warranty claims must be directed to an IAG Certified Engine Installer for assignment of a return merchandise authorization number (RMA). Following the issuance of an RMA claim number, IAG requires the engine to be returned to our facility for inspection and final determination of claim eligibility. The client must authorize the Certified Engine Installer to remove the engine from the vehicle. The client is responsible for all shipping and handling costs to return the engine to IAG. Upon receipt of the engine, IAG will disassemble the engine to determine the cause of failure. After engine teardown is complete, IAG will determine whether warranty coverage applies. If the engine is deemed to be covered under warranty, IAG will reimburse the Certified Engine Installer for a pre-determined cost of labor. If the engine is not deemed to be covered under this limited warranty, the client will be responsible for all labor costs associated with the removal and reinstallation of the engine or components.

    Write Your Own Review
    You're reviewing:IAG Performance Stage 4 Extreme EJ25 Closed Deck Shortblock