Sale

Engines and Components› Engines, Blocks and Components

IAG Performance

Stage 2.5 International Hybrid EJ25 Closed Deck Short Block

$5,599.99 $4,899.99 Save $700.00

SKU: IAG-ENG-1252.IH

Special Order
Special Order
Ships in 4–6 weeks
Free Shipping over $200
$100 Minimum Order
30 Days Return
INSTALL DIFFICULTY
DIY PRO SHOP

Professional / shop required

Overview

The IAG Performance Stage 2.5 International Hybrid EJ25 Subaru Closed Deck Short Block is designed to increase displacement and low-end torque for vehicles originally equipped with an EJ20 2.0L engine. This short block features IAG-Spec JE FSR 99.75mm forged pistons with a 8.5:1 compression ratio, designed to match EJ20 cylinder heads without modification. The block is converted to a closed deck configuration using brand new Subaru OEM case halves, machined to accept IAG's closed deck inserts.
Show original supplier description
The IAG Performance Stage 2.5 International Hybrid EJ25 Subaru Closed Deck Short Block is meticulously crafted for enthusiasts seeking to enhance the displacement and low-end torque of their EJ20-equipped vehicles. This hybrid block allows for increased capacity without the need for modifying EJ20 cylinder head chambers, thanks to its specially designed pistons that manage compression. Construction begins with new Subaru 2.5L engine case halves, which are precisely CNC machined and fitted with IAG's robust CLOSED Deck Inserts to create a solid deck structure. These inserts incorporate small passages to maintain essential coolant flow. The block is then Deck Plate bored and honed to 99.75mm using an in-house Sunnen SV-30, enabling custom piston-to-wall clearances tailored to specific needs. Assembly involves a new 2017+ Subaru 2.5L nitride-treated STI crankshaft paired with ACL or King race main bearings. IAG-Spec Tuff H-Beam connecting rods, secured by ARP rod bolts, are used with matching ACL or King race rod bearings. The case halves are sealed with new OEM main/case bolts and sealant. The build is completed with IAG-Spec 99.75mm JE FSR 2618 Forged Pistons featuring .210" steel wrist pins, offering superior durability and performance capabilities.

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.

Fitment

Fitment Guaranteed

Don’t gamble
on fit.

Log your build in the MOTORMIA app and we’ll guarantee this part fits your exact setup — or your money back, return shipping covered.

Available on iOS & Android

Specifications

BrandIAG Performance
Part NumberIAG-ENG-1252.IH
CategoryEngines and Components
5,000+ Trusted brands
1M+ Enthusiasts
5M+ Parts sold
(760) 282-4645 hello@motormia.co

Buy with Confidence

Returns & Fitment

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.

View Full Return Policy

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.

Free shipping over $200 in the continental US. Alaska, Hawaii, U.S. territories (Puerto Rico, U.S. Virgin Islands, Guam, American Samoa, and the Northern Mariana Islands), and international orders carry surcharges — most appear at checkout. Some exceptions (LTL freight, or suppliers who quote freight only after we place the order) won’t. In those cases we’ll reach out with the exact charge before your order moves forward.

View Full Shipping Policy