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IAG Performance

IAG Stage 4 EXTREME 2.5L Subaru Closed Deck Short Block

$299.99

SKU: IAG-ENG-1453

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Overview

The IAG-ENG-1453 is a Stage 4 Extreme 2.5L Subaru Closed Deck Short Block. It is professionally built and assembled to handle more boost and power, making it ideal for high-powered street or race cars. The block features brand new Subaru OEM case halves converted to closed deck, with IAG Fire-Lock receiver groove machining.
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The IAG Stage 4 EXTREME 2.5L Subaru Closed Deck Short Block is engineered for high-powered street cars and purpose-built race cars, designed to withstand significantly more boost and power output than a stock engine. This professionally built and assembled short block starts with brand new Subaru 2.5L OEM case halves that are converted to a closed deck configuration using IAG's inserts. The block is then meticulously machined to accept 14mm head studs and features IAG's revolutionary Fire-Lock receiver groove machining for enhanced sealing with IAG Fire-Lock Head Gaskets, crucial for high boost applications. Internally, the short block is equipped with IAG-Spec JE FSR 99.75mm 2618 forged pistons, .250″ / .927″ H13 performance wrist pins and clips, IAG Spec Tri-Beam connecting rods secured by ARP625+ rod bolts, and ACL rod and main bearings. A Manley Billet Turbo Tuff Crankshaft and ARP Main Case Bolts complete the rotating assembly. The displacement is 2.5L with a bore size of 99.75mm. It is important to note that the final compression ratio is dependent on the cylinder heads used. With B, V, and W cylinder heads (EJ257), the compression ratio is 8.2:1, while D cylinder heads (EJ255) result in an 8.5:1 ratio. This short block has a power output rating of 1100 Bhp. The product requires separate purchase of head studs and IAG Fire-Lock Head Gaskets for proper installation and operation.
Vehicle Symptoms
  • loud knocking or rod knock under load
  • excessive oil consumption and blue smoke
  • low compression in one or more cylinders
  • coolant loss or overheating after hard driving
  • rough idle and misfire across cylinders
Diagnostic Codes
  • P0300 – random/multiple cylinder misfire
  • P0301 – cylinder 1 misfire detected
  • P0302 – cylinder 2 misfire detected
  • P0303 – cylinder 3 misfire detected
  • P0304 – cylinder 4 misfire detected
  • P0217 – engine coolant overtemp condition
  • P0522 – engine oil pressure sensor/switch low input
  • P1341 – persistent misfire
Relevant Conversations
  • IAG Stage 4 Extreme closed deck short block review
  • Subaru EJ257 rod knock causes and replacement cost
  • P0300 misfire after engine rebuild – what next?
  • IAG closed deck vs Outfront Motorsports closed deck
  • How long does it take to install an IAG short block?
  • Best oil pump and pan for IAG stage 4 block
  • Subaru low oil pressure at idle after hard driving
  • EJ25 closed deck short block for 600whp build
  • IAG-ENG-1453 compatible with 2015 WRX?
  • Signs of a cracked ringland on Subaru STI

Product descriptions are provided by our supplier partners and may not always be perfectly accurate. Not sure this fits? or call (760) 282-4645 and we’ll verify before you order.

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Specifications

BrandIAG Performance
Part NumberIAG-ENG-1453
CategoryEngines and Components
5,000+ Trusted brands
1M+ Enthusiasts
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(760) 282-4645 hello@motormia.co

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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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Shipping

Orders are processed in 1–3 business days. In stock parts ship promptly from our partner network. Special-order items either aren’t currently stocked or are built to your spec — expect 4–6 weeks. If a part goes on backorder while your order is in the queue, we’ll reach out and work through discounted alternatives together.

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