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, .180" Chromoly 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.

Power:

• The IAG Stage 2 Tuff Short Block has a power output rating of 625BHP.

Compression Ratio:

• 8.5:1 on D Cylinder Heads (EJ255)
• 8.2:1 on B, V and W EJ257 Heads with standard thickness gasket.

Additional Options Available:

• Oil Pump - Subaru JDM 12mm High Volume Oil Pump or 11mm Subaru Oil Pump (Sold Separately)
• Hardware/Seals - OEM cover and seal kit (Sold Separately)

Not planning on reusing your original short block service plugs and covers? IAG offers a simple comprehensive cover and seal kit that includes:

• (1) Rear main seal
• (3) OEM wrist pin plugs
• (3) OEM wrist pin plug washers
• (1) OEM separator cover
• (6) OEM separator cover bolts
• (1) OEM wrist pin service cover
• (1) OEM wrist pin service cover O-ring
• (2) OEM wrist pin service cover screws.

If you are reusing your original wrist pin service plugs and covers always replace the following components before installing a short block to avoid potential leaks:

• (3) OEM wrist pin plug washers
• (1) wrist pin service cover O-ring

Never reuse a rear main seal on a new short block.

Note: All IAG Short Blocks are balanced and blueprinted.

Please review the PDF document below regarding installation, break-in procedures and warranty information.