IAG Stage 3 Extreme Subaru EJ25 Closed Deck Short Block The IAG Stage 3 Extreme Short Block starts with brand new Subaru 2.5L engine case halves. IAG machines the case halves assembled together in our Haas VF-4SS CNC mill to accept the IAG CLOSED Deck Inserts that transform the block into a solid deck. The unique inserts feature small passages that allow needed coolant flow to the deck surface. The case halves are then CNC machined with o-ring receiver grooves around the bore surface as well as drilled and tapped to accept larger 1/2″ head studs that aids in preventing cylinder heads from lifting in high boost applications. Next the short block is Deck Plate bored and honed to 99.75mm in our in-house Sunnen SV-30 the most advanced automotive cylinder hone available. IAG?s in-house honing process is able to set custom piston to wall clearances to best fit your needs. The modified case halves are then assembled using a new 2017 Subaru 2.5L nitride treated STI crankshaft that is matched to ACL or King race main bearings. Manley Turbo Tuff Tri-Beam connecting rods and ARP rod bolts are utilized along with ACL or King race rod bearings. The case halves are sealed with new OEM main/case bolts and sealant (upgrade to ARP mains and line hone service a la carte). IAG-Spec JE FSR 99.75mm Forged Pistons are chosen to finish the Stage 3 Extreme short block. Stage 3 Extreme Closed Deck Includes: Case Halves – Converted to Closed Deck using brand new Subaru OEM case halves bored and honed to 99.75mm. O-Ringing – Machine and O-Ringed Deck Surface Head Studs – Machine case to fit 1/2″ head studs – *Head studs sold separately Pistons – IAG-Spec JE FSR 99.75mm 2618 Forged Pistons Ring Set .180″ Chromoly wrist pins Clips (Perfect Skirt Coating and Offset Wrist Pins) Connecting Rods – Manley Turbo Tuff Tri-Beam / ARP2000 Rod Bolts. Rod / Main Bearings – ACL or King Race bearings. Crankshaft – Standard New Subaru Nitride Treated 2017 STI Crankshaft. Case / Main Bolts ? Standard FHI Subaru case bolts. Additional Options Available: Oil Pump – Subaru JDM 12mm High Volume Oil Pump or 11mm Subaru Oil Pump Head Studs – IAG Performance 1/2″ head stud set manufactured by ARP Head Gaskets – JE Pro Seal .039″ Head Gaskets Hardware / Seal Option – (PN# IAG-ENG-1720) – Wrist pin plugs washers separator cover bolts etc. In case you don?t want to transfer from the original engine. Compression Ratio: 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 Recommends JE Pro Seal .039 inch head gaskets Power: The IAG Stage 3 Extreme Short Block has a power output rating of 800BHP. *All IAG short blocks are balanced and blueprinted.