The IAG Stage 1 Short Block is perfect for lightly modified EJ25 Subaru's that need a basic and reliable performance short block. Subaru turbo engines are commonly known for piston ring land failures and if gone unchecked lead to rod knock and total engine failure due to oil starvation from blow by. IAG's Stage 1 Short Block includes upgraded forged pistons along with performance main and rod bearings that replace the OEM components that are prone to common failure on Stage 2 and up vehicles.

Each IAG Stage 1 Short Block starts with a new Subaru 2.5L 99.5mm bore EJ25 engine case halves as standard. The short block is measured and assembled using a new 2017+ Nitride Treated Subaru 2.5L STI crankshaft that is matched to ACL or King main bearings. Early style OEM STI rods are utilized along with ACL or King rod bearings. The case halves are sealed with new OEM case bolts and sealant. Finally, 99.5mm IAG-Spec JE Forged Pistons are spec'd and installed finishing off the short block.

Stage 1 Short Block Includes:

• Case Halves - Brand new Subaru OEM case halves 99.5mm Stock Bore
• Pistons - IAG-Spec JE 99.5mm Forged Pistons, Ring Set, .180"" Chromoly Steel Pins, Clips, (Perfect Skirt Coating and Offset Wrist Pin)
• Connecting Rods - Early OEM (Stronger Style) STI rods
• Rod / Main Bearings - ACL or King Bearings
• Crankshaft - Standard New Subaru Nitride Treated 2017+ STI Crankshaft
• Case / Main Bolts - Standard FHI Subaru case bolts

Power:

• The IAG Stage 1 Short Block has a power output rating of 475BHP.

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:

• 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 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.