Have Questions?

IAG STAGE 4 TUFF EJ25 SUBARU CLOSED DECK SHORT BLOCK FOR WRX, STI, LEGACY GT, FORESTER XT

2 sold in last 8 hours
IAG-ENG-1452
$6,599.99
Snap Logo Lease for as low as $/week Learn More

customers are viewing this product
IAG STAGE 4 TUFF EJ25 SUBARU CLOSED DECK SHORT BLOCK FOR WRX, STI, LEGACY GT, FORESTER XT
IAG Stage 4 Tuff Subaru EJ25 Closed Deck Short Block 

The IAG Stage 4 Tuff Short Block starts with brand new Subaru 2.5L engine case halves. IAG machines the case halves assembled together in our Haas VF-4SS CNC mill 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 Tuff case is then drilled and tapped to accept 14mm head studs that combined with the IAG Fire-Lock head gasket set greatly reduces head gasket failure during high cylinder pressure scenarios. Next, the short block is 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 new 2017+ Subaru 2.5L nitride treated STI 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 new OEM main/case bolts and sealant (upgrading to ARP mains requires line honing). Finally, IAG-Spec 99.75mm JE FSR 2618 Forged Pistons with electroless nickel plated tops and ring area as well as upgraded .250" / .906" H13 wrist pins are added to finish the Stage 4 Plus 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 H13 tool steel and the pin piers are profiled to increase pin boss strut. 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 Tuff Closed Deck 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 to fit 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 Tri-Beam +2mm w/ 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.

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 High Volume Oil Pump - $219, or Subaru 11mm 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 (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 Tuff Short Block has a power output rating of 1000BHP.

    Fitment-
    2002-2005 WRX (Requires Mods)
    2006-2014 WRX
    2004+ STI
    2005-2009 Legacy GT
    2004-2013 Forester XT

    *All IAG short blocks are balanced and blueprinted.

    *Pictures used for marketing purposes only, actual product may vary 
    Read More
    Read Less
    Returns Policy

    Returns may be accepted within 14 days of purchase pending Return Merchandise Authorization (RMA). No returns or cancellations on special order items. All returns will be charged a 20% restocking fee, no exceptions.

    To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging. Item must be able to be resold as new. Several types of goods are exempt from being returned. Hazardous materials, fluids, greases, chemicals, and clothing are not able to return.

    Free shipping is available within the lower 48 states for most orders totaling $199 or more. A free shipping option will be available during checkout. This offer is for delivery address in the continental United States and excludes shipments going to Alaska, Hawaii, Military Boxes, and items that require freight shipping.

    Processing Time
    Patterson Performance stocks a large quantity of items at any given time. Some items may require drop shipping from one of our various distributors. In stock items will ship within 1-2 business days. If you're needing your product quickly, please contact us to verify product availability before placing your order. Orders requiring additional verification (security concerns, incorrect information, etc.) may need additional processing time. Estimated shipping dates are not guaranteed and are subject to change based on inventory levels and manufacturer lead times. Backordered items are shipped immediately once available.

    Items ship daily, If the item you ordered is not in stock, a member of our team will contact you via email / phone.

    Patterson Performance will only ship to an address that varies from your billing address if payment is made via Paypal or a financing partner.

    Patterson Performance ships from multiple warehouses throughout the United States, and sometimes from manufacturers overseas.

    You can simply contact us via email / telephone for a live inventory check

    P65 WARNING: Cancer and Reproductive Harm

    Find more information at www.P65Warnings.ca.gov.

    Customer Reviews

    ×

    Someone recently bought a

    The cookie settings on this website are set to 'allow all cookies' to give you the very best experience. Please click Accept Cookies to continue to use the site.

    Your cart

    ×