IAG Stage 2 Tuff "Cosy" 2.5L Subaru Short Block for WRX, STI, Legacy GT, Forester XT

IAG Stage 2 Tuff Cosy 2.5L Subaru Short Block for Subaru WRX, STI, Forester XT and Legacy GT.
IAG Stage 2 Tuff "Cosy" Built 2.5L Subaru Short Block

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MSRP: $5,039.99
Our Price: $4,799.99
Savings: $240.00

Availability: Usually Ships in 3 to 4 Weeks
Part#: IAG-ENG-1212

Seal Kit*:
Wrist Pin / Cover Seals P# IAG-ENG-1720 [Add $105.99]
Not Required

Shipping Method*:
IAG Pelican Case
Cardboard Box

Description Applications

IAG Stage 2 Tuff "Cosy" Short Block

IAG Performance is proud to embrace our partnership with Cosworth Performance by offering a variation of our top-selling Stage 2 TUFF block featuring Cosworth 99.75mm Forged Pistons and connecting rods. The IAG Stage 2 Tuff "Cosy" short block starts with new Subaru 2.5L EJ25 engine case halves that are bored and honed to 99.75 on our in-house Sunnen SV-10. IAG's in-house honing process is able to set piston to wall clearances tighter for a quieter running engine. The short block is measured and assembled using a new 2017+ Subaru 2.5L nitride treated STI crankshaft that is matched to ACL or King race main bearings. Next Cosworth 4340 forged connecting rods with Cosworth H11 tool steel rod bolts (260,000psi) are utilized to increase the power rating slightly at the expense of being heavier. The connecting rods are matched to ACL or King race rod bearings. The case halves are sealed with new OEM main case bolts and sealant. Finally, 99.75mm Cosworth forged pistons finish off the short block.

The IAG Stage 2 Tuff "Cosy" Short Block has a power output rating of 675BHP.

Stage 2 Tuff "Cosy" Short Block Includes:
  • Case Halves - Brand new Subaru OEM case halves, bored and honed to 99.75mm.
  • Pistons - Cosworth 99.75mm Forged Pistons
  • Connecting Rods - Cosworth / Cosworth H11 Rod Bolts (260,000psi).
  • 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:
  • Hardware / Seals - OEM cover and seal kit - $105.99

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

*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 OEM cover and seal kit that includes (1) Rear main seal, (3) wrist pin plugs, (3) wrist pin plug washers, (1) separator cover, (6) separator cover bolts, (1) wrist pin service cover, (1) wrist pin service cover O-ring and (2) wrist pin service cover screws. *If you are reusing your original wrist pin service plugs and covers always replace the (3) 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.

Optional Shipping Methods:

Red Carpet Service - IAG Pelican Case (Recommended):
Subaru EJ25 Seal Kit

Red Carpet Service / IAG Pelican Cases are a premium shipping option offered by IAG. Your IAG short block is shipped via a returnable polypropylene military grade IAG Pelican case, which provides optimal protection while in transit. Please contact an IAG sales associate at (410)-840-3555 within 2 business days of your purchase to provide credit card confirmation and approval for Pelican shipping - further details and logistics are explained in our Post Sale PDF document, which can be found below. The IAG Pelican case must simply be returned to IAG within 7 days of the receipt of your engine and carries no additional cost vs. cardboard box shipping. If the case is not returned in the required timeline, a core charge of $399 is placed on your card.

Cardboard Box:
Blocks can alternatively be sent in a standard cardboard box, but bear a greater risk of damage in transit. While cost is the same, we suggest a Pelican case that ensures safe transit.

Please review the PDF document below regarding installation, break-in procedures, warranty information, and our Pelican Case Shipping Service. After ordering your block, please call our sales team at 410-840-3555 to approve Pelican shipping and secure the safest shipping method in the aftermarket!

PDF After Sale Document - Contains Shipping, Engine Care and Warranty Information

  • Cosworth 99.75mm Forged Pistons, Ring set, Pins and Clips
    IAG Spec Bore and Hone (Performed on our in-house Sunnen SV-10)
    Tighter piston to wall clearance for quiet operation
    New FHI Subaru Case Halves (Bored, Honed and Plateau Brushed)
    Cosworth Forged Connecting Rods w/ Cosworth Rod Bolts
    New FHI Subaru Nitride Treated 2017+ STI Crankshaft
    ACL or King Race Rod Bearings
    ACL or King Race Main Bearings
    New FHI Main Case Bolts
    IAG Spec Blueprint Sheet
    Power Output Rating: 675BHP

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