IAG / Crest CNC Billet Aluminum EJ25 Subaru Case Halves For WRX, STI, Forester XT & Legacy GT




Collections: Engine

Product type:

Vendor: IAG




The CNC Billet Aluminum 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 IAG / Crest CNC EJ Block, (Formerly Willall) is machined from 6061-T6 Aerospace Aluminum and features Darton Ductile Iron Sleeves. The block is designed with increased material thickness over the OEM cast aluminum case halves and adds a unique 4-bolt bottom end for additional strength.

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

Additional Options:

  • Bore & Hone: Bore & Hone to customer specification
  • Fire-Lock: Fire-Lock machine the deck surface
  • Case Bolts: ARP Case Bolts
  • Head Studs: IAG / ARP 14mm Head Studs, nuts, and washers - *14mm head studs are required for this block
  • Machining Deck: - Machine head gasket deck surface

Minimum Requirements To Build & Assemble:

  • *ARP Case Bolts (Sold separately)
  • 14mm Head Studs (Sold separately)
  • Internal components (Pistons, Rods, Bearings, Crank, All sold separately).
  • Decking head gasket surface required