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IAG Performance / Willall Stage X 2.5L 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 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
Additional Options Available:
  • Head Studs - IAG / ARP Spec 14mm head studs, nuts, and washers - $550
  • Oil Pumps - Subaru JDM 12mm Oil Pump - $219 / OEM Subaru 11mm Oil Pump - $199.95
  • 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).
Required:
  • *IAG Fire-Lock .051" Head Gaskets with IAG-Spec Alloy Ring Set* PN# IAG-ENG-1740
  • 14mm Head Studs
Compression Ratio:
  • 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. 



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