The IAG Stage 2 Tuff short block starts with new Subaru 2.5L EJ25 engine case halves that are bored and honed to 99.75 on our in-house Sunnen SV-30 the most advanced automotive cylinder hone available. IAG’s in-house honing process is able to set piston to wall clearances tighter for a quieter running engine. The short block is measured and assembled using a new 2017+ Subaru 2.5L nitride treated STI crankshaft that is matched to ACL or King race main bearings. Next, IAG-Spec Tuff H-Beam rods with ARP Rod Bolts are utilized to increase the power rating slightly at the expense of being slightly heavier. The connecting rods are matched to ACL or King race rod bearings. The case halves are sealed with new OEM main case bolts and sealant. Finally, IAG-Spec JE 99.75mm Forged Pistons are added to finish off the short block.
Stage 2 Tuff Short Block Includes:
Case Halves -Brand new Subaru OEM case halves, bored and honed to 99.75mm.
Pistons -IAG-Spec JE 99.75mm Forged Pistons, Ring Set, .210″ 9310 Steel Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pin)
Connecting Rods -IAG-Spec Tuff H-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
IAG Oil Pickup – Upgraded oil pickup featuring heavy gauge steel tubing, 2 point bracket & mesh filter
IAG Oil Baffle – Upgraded oil control baffle and windage tray
IAG Oil Pickup & Baffle Set – Upgraded oil pickup, oil control baffle, and windage tray
Hardware / Seals -OEM cover and seal kit
8.5:1 on D Cylinder Heads (EJ255)
8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.