IAG Performance / Willall Stage X 2.5L Subaru Billet Aluminum Short Block For WRX, STI, LGT, FXT
Using the same world-leading technology found in Willall’s incredible billet GT-R block, the billet EJ case seeks to change the Subaru performance tuning market by reinventing the EJ and addressing virtually every weakness that exists in max-power builds. The Stage “X” Block is a complete short block built on the Willall billet platform, which also includes pistons, rods, bearings, crank, bore/hone, case bolts, line hone, and final assembly and blueprinting.
Stage X Billet EJ25 Case Features:
Machined from solid billet 6061-T6 Aerospace grade aluminum
Darton Ductile iron sleeves
Increased material thickness in all known weak points (around head studs, bottom end location)
Unique 4 bolt bottom end strengthening
Threads are rolled into the block rather than conventionally cut for much greater strength
Full cooling system operation
Radiused coolant and oil galleries for improved flow and less foaming/turbulence
Fits all factory engine bay ancillaries (i.e. AC/PS/etc.)
Multiple Times stiffer and stronger than the stock case
Precision machined for a superior surface finish
Hard anodized to avoid marking or straining
IAG Stage X Complete Shortblock Includes:
Case - WREJBB Billet / Sleeved Case Halves
Fire-Lock - IAG Fire-Lock receiver groove machining, latest solution to prevent head gasket failure on high horsepower and high boost Subaru's - *IAG Fire-Lock head gaskets required
Machining - Machined for 14mm Head Studs *(Studs sold separately / Note the proper head gaskets or head gasket modifications are required for proper fitment with 14mm studs.
Pistons – IAG-Spec JE FSR 99.75mm 2618 Forged Pistons, Electro-nickel Plated Tops & Ring area, Ring Set, .250" / .927" H13 Wrist Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pins)
Connecting Rods – IAG-Spec +2mm Tri-Beam w/ ARP625+ Rod Bolts
Rod/Main Bearings – ACL/King Race Bearings
Crankshaft – Manley Billet Crank
Case / Main Bolts – ARP Main Bolts
*IAG Fire-Lock .051" Head Gaskets with IAG-Spec Alloy Ring Set* PN# IAG-ENG-1740
14mm Head Studs
8.5:1 on D Cylinder Heads (EJ255)
8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.
The IAG / Willall Stage X Short Block has a power output rating of 1100+BHP.
*All IAG short blocks are balanced and blueprinted.
Not planning on reusing your original short block service plugs and covers? IAG offers a simple comprehensive cover and seal kit that includes (1) Rear main seal, (3) OEM wrist pin plugs, (3) OEM wrist pin plug washers, (1) OEM separator cover, (6) OEM separator cover bolts, (1) OEM wrist pin service cover, (1) OEM wrist pin service cover O-ring and (2) OEM wrist pin service cover screws. *If you are reusing your original wrist pin service plugs and covers always replace the (3) OEM 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.
Model Year & Fitment
2002-2005 Subaru WRX (Requires Mods)
2006-2014 Subaru WRX
2004-2018 Subaru STI
2005-2009 Subaru Legacy GT
2004-2013 Subaru Forester XT
Availability: Usually Ships in 4 to 5 Weeks
This year has proven to be a bit different than expected, so we must note that there is the potential for shipping and inventory delays due to scarcity and other factors impacting our world. DRP remains fully committed to pursuing the completion of your purchase within a reasonable manner under the current circumstances. Feel free to contact us to confirm availability of your favorite items!
This product can expose you to chemicals including Lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov