The Cosworth EJ25 (STI) short block has gone through countless hours of dyno evaluation to determine the best combination of parts to guarantee performance and reliability. Each EJ25 short block starts with a brand new Subaru case. The case is inspected and then the bores are "Diamond" honed to perfection to receive High Compression Cosworth Forged Pistons.
Cosworth then balance the rotating assembly that includes a Cosworth 81mm billet stroker crank and Cosworth Forged H-Beam Connecting Rods to within .5 gram. The select parts are professionally assembled by one of Cosworths skilled engine builders using their own, tri metal race spec bearings.
For added performance, call us about Cosworth CNC ported Big Valve Cylinder Heads and high performance camshafts.
- New Subaru EJ25 STI Engine case
- Billet 81mm Stroker Crankshaft
- Cosworth Forged H-beam Connecting Rods
- Cosworth Forged High Compression Pistons and rings
- Cosworth Tri-metal bearings
- Balanced to within .5 gram
- Complete blue-print assembly
- Ring gap checked
- Bearing clearance checked
- Diamond Honed
- Deck height checked
- Connecting Rod side clearance checked
- Crankshaft end float checked
- Shipped with protective covers
About Manufacturer: Cosworth
Over the last 50 years Cosworth have developed an in-depth knowledge of engines, electronics and a range of high performance technologies. This has been used to supply some of the most successful motor sport teams and vehicle manufacturers in history.
Our unprecedented success has fueled customer demand globally from diverse market sectors designing and developing technologies and components for aerospace, automotive, defense and sport applications.