IAG / WILLALL STAGE X EJ25 SUBARU BILLET ALUMINUM SHORT BLOCK (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 stock case
- Precision machined for superior surface finish
- Hard anodized to avoid marking or straining
IAG Stage X Complete Shortblock Includes:
- Case - WREJBB Billet / Sleeved Case Halves
- Pistons – IAG-Spec 99.75mm 2618 Forged Pistons w/ Extreme .210” 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 Bolts – ARP Main Bolts
- 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.
Additional Options Available:
- Head Studs - IAG / ARP Spec 14mm head studs, nuts, and washers - $550
- Head Gaskets - IAG Cooper Fire Ring .051" Head Gasket with 14mm Head Stud Provisions for high horsepower, high boost applications - $219.98 *Note specific gaskets are required for this block.
- Oil Pumps - Subaru JDM 12mm Oil Pump - $219 / OEM Subaru 11mm Oil Pump - $194.95
- Hardware / Seal Option - $105.99 (Includes: Wrist pin plugs, washers, separator cover, bolts, etc. In case you don’t want to transfer from the original engine).
- 14mm Head Studs, Head Gaskets, Oil Pump all sold separately, and are required to run.
- 8.5:1 on D Cylinder Heads (EJ255)
- 8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.
Head Gasket Recommendations:
- *IAG Cooper Fire Ring .051" Head Gasket with 14mm Head Stud Provisions for high horsepower, high boost applications
The IAG / Willall Stage X Short Block has power output rating of 1000+BHP.
*All IAG short blocks are balanced and blueprinted.
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