SKU: M45-1011 M45 Stage 2.5 EJ25 Closed Deck Short Block for WRX, STI, Legacy GT, Forester XT

Strictly Business

The EJ25 comes from the factory with an open-deck design, which provides better cooling efficiency and is lighter for general use. However, for those seeking more power, particularly in high-performance or racing applications, an aftermarket closed-deck conversion is a popular choice.

Closed Deck Spec

This closed-deck short block is designed to ensure the longevity of your vehicle's performance and to handle higher horsepower and torque levels that typically distort or crack open-deck blocks. The engine case, composed of new Subaru OEM case halves, is modified to accommodate the Closed Deck inserts, effectively turning the block into a sturdy deck. The block is then drilled and tapped for the 1/2" head studs. It's ideal for high-performance builds, offering better durability and longevity in racing applications. This added rigidity also leads to more consistent power delivery by ensuring reliable combustion under extreme conditions.

Precision Executed

The engine case, using new OEM case halves, has been subjected to a thorough Bore and Deck process. This includes precision boring and honing of the case halves, ensuring perfect fitment and alignment. A torque plate is utilized during the honing process to enhance the precision further, resulting in a flawless engine case that guarantees optimal performance.

Unmatched Durability

At the heart of this short block is a new OEM Subaru Nitride-Treated Crankshaft, designed for peak performance and durability in:

• 2004-21 STI
• 2006-14 WRX
• 2004-08 Forester XT
• 2005-09 Legacy GT

Built to fit all EJ25 engines, this crankshaft ensures a strong foundation for reliability.

The Power of Forged Connecting Rods

Get ready to unleash serious power with Callies Ultra Enforcer connecting rods, engineered for racers pushing the limits of high-boost and extreme horsepower setups. These rods are built to handle an insane 300 horsepower per cylinder, making them the ultimate choice for heavy-duty applications. With beefed-up mass and precision pressure angle arches, you’ll get rock-solid wrist pin stability, while the AMPCO 45 pin bushings tackle the heaviest loads. Machined from ultra-tough 4330 vanadium-enhanced steel, and featuring reinforced tower flanges and bolt gussets, these I-Beam rods offer unmatched resistance to bending, twisting, and keep your bearings locked in tight under massive power!

Premium Wiseco Subaru EJ257 WRX/STI AP Forged Piston Kit

Forged pistons, known for their exceptional strength and wear resistance, add significant value to the engine's performance and overall durability. If it's modified for more power, the stock cast pistons may not be able to withstand the increased stress. This is where forged pistons come in. We have also equipped the engine with high-grade piston rings and seals, improving the engine's compression and oil control. The pistons come standard with our ArmorGlide coating material for reduced friction and noise, freeing up horsepower.

To Sum It Up

• New OEM case halves
• New OEM Subaru nitrided crankshaft
• Upgraded Wiseco forged pistons with new piston rings and seals
• Forged I Beam Callies Compstar Rods
• ACL or King hardened rod bearings and main bearings
• Fits WRX 2006-2014, STI 2004-2021, Legacy GT 2005-2009, Forester XT 2004-2013, Outback XT 2005-2009.

Make it Stout with ARP

ARP studs offer precision alignment and are thread-rolled after heat treatment, boosting fatigue strength by 1000%. Despite the higher cost, this process ensures superior durability. Each kit includes premium washers. Essential for performance engines under increased boost, ARP head studs are the top choice for your WRX or STI, providing an option to enhance your engine’s strength.

Warranty

M45 Automotive's warranty covers against defects in our workmanship and product for 24 Months or 24,000 Miles (whichever comes first) from the date of receipt.

Core Charge

Unlike traditional practices, we do not require an up-front core charge when you purchase our product. Instead, we offer a convenient and hassle-free process for returning your old short block, ensuring a smooth transaction for both parties.

By making a purchase from us, you agree to promptly deliver your core (old short block) within 30 days from the date of purchase. It is crucial to adhere to this time frame to avoid any inconveniences. After the 30-day period, failure to return your core will result in the voiding of your warranty and a charge of $1000.

We pride ourselves on our commitment to customer satisfaction and understand that cores may have various issues. Rest assured, we accept your core regardless of its condition, as long as it matches the exact specifications and includes all the parts that originally came with it.

Our streamlined core return process ensures that you can enjoy the benefits of your purchase while fulfilling your responsibility to return the core in a timely manner. We appreciate your cooperation in helping us maintain the quality of our products and guaranteeing a positive experience for all our valued customers.

Freight Shipping

To make the process as straightforward as possible, we charge freight up front for both the outbound shipment of your new short block and the inbound return of your core. This ensures that you know the total shipping cost right from the start, without any surprises.