IAG Performance / Crest CNC Stage X 2.5L Subaru Billet Aluminum Short Block

IAG Performance / Crest CNC Stage X Billet Aluminum Short Block for 02-14 WRX, 04-21 STI, 05-09 LGT, 04-13 FXT

THE ULTIMATE EJ PLATFORM

The IAG Performance / Crest CNC 2.5L Subaru Billet Aluminum Short Block was created to reinvent the EJ platform by addressing virtually every weakness found in max-power builds. The Stage X is engineered to eliminate case flex in high-power EJ applications, enabling a foundation that can reliably support a 1150+ BHP capable build with the proper supporting components.

Built around Crest billet / sleeved case halves, the Stage X pairs high-end rotating and valvetrain-ready machining with IAG’s Fire-Lock™ sealing strategy and 14mm head stud-ready machining. This is the go-to option when you’re building a no-compromise EJ for extreme boost and racing use.

BUILT WITH CNC BILLET/SLEEVED CASE HALVES

Crest CNC billet / sleeved case halves are at the heart of the Stage X block. Each billet case half is machined on precise CNC equipment and stress relieved to ensure maximum structural integrity. Crest sleeves are installed with precise interference fit and machined for a finish bore of 99.75mm, maintaining an ideal foundation for performance builds.

This process eliminates many of the weak points in the cast OEM EJ case — especially near the case bolt reliefs and at high RPM / high torque points — making the Stage X block an ideal choice for punishing power levels and extreme racing conditions.

FIRE-LOCK™ & 14MM HEAD STUD READY

To ensure proper head gasket retention under high cylinder pressure, the Stage X block features IAG’s Fire-Lock™ receiver groove machining. Fire-Lock™ separates combustion sealing from fluid sealing, allowing superior sealing at high boost levels (IAG Fire-Lock™ head gaskets required and sold separately).

The case halves are also CNC machined for 14mm head stud fitment, enabling builders to use high-strength 14mm stud kits for improved clamping force and sealing integrity.

FORGED JE PISTONS & TRI-BEAM RODS

Each Stage X short block includes premium forged JE pistons and IAG-Spec +2mm Tri-Beam connecting rods with ARP 625+ rod bolts. The pistons feature electroless nickel plated tops & ring areas, while the connecting rods and wrist pins are designed to support higher bore and stroke loads associated with extreme power builds.

PREMIUM BEARINGS & ROTATING ASSEMBLY

ACL or King race rod and main bearings are installed, along with an IAG-Spec billet 79mm crankshaft specially suite for high load and race environments. Every rotating component is balanced and blueprint-matched to the block assembly, ensuring consistency and reliability in high-stress conditions.

STAGE X BILLET SHORT BLOCK INCLUDES

What's Inside:

• Case Halves – Crest CNC billet / sleeved case halves
• Pinned Mains – Machined for 9.5mm pinned mains
• Fire-Lock – IAG Fire-Lock™ receiver groove machining (IAG Fire-Lock™ head gaskets required)
• Machining – CNC machined for 14mm head studs (studs sold separately)
• Pistons – JE 99.5mm FSR 2618 custom forged pistons, JE ProSeal ring set, .250" H13 .927" tool steel wrist pins, clips
• Connecting Rods – IAG-Spec +2mm Tri-Beam forged connecting rods with ARP 625+ rod bolts
• Rod / Main Bearings – ACL race bearings
• Crank – IAG-Spec billet 79mm crankshaft
• Case / Main Bolts – ARP case bolts

Power Rating:

The Stage X Billet Short Block is engineered for builds targeting 1150+ BHP with the appropriate supporting modifications.

Please Note: This item is not eligible for standard ground shipping and must be delivered via freight. 
STOCK NOTICE: This item is built to order and carries a minimum 6-8 week build time.

IMPORTANT DELIVERY NOTE: Your order is shipping Via Truck Freight which requires you to be available at the time of receipt. There is a possibility the trucking company will try to schedule a delivery time with you. At the time of delivery, the driver will hand you the delivery receipt also referred to as the bill of lading, you will use this to notate any damages to the shipment. It is important that you fully inspect the shipment from all sides and notate any dents, punctures or rips in the outside packaging on the delivery receipt. Once you've inspected your shipment from the outside, you will need to open it and check the product in its entirety for damages and notate them if any. If there is no damage sign for the package and enjoy! In the rare case, you do find that your order arrived with damages, it is important you follow these steps. - Do not refuse the product- Document the damages in as much detail as possible on the Bill of Lading
- Take numerous photos from all angles (including packaging)
- Keep the product and contact the shipping company to start the damage claim
- Contact us either by phone or email for the next steps In the situation where the delivery driver is unable to wait for you to open and inspect your product, simply document "driver was unable to wait for inspection." All damage must be noted on the Bill of Lading before signing and initiating a damage claim. If the damage is not notated before signing for the item it is assumed to be in good condition. This will forfeit the ability for a shipping claim and you will not be eligible for refund or replacement.