New Subaru OEM EJ255 Short Block Engine Part #10103AC880

New Subaru OEM EJ255 Short Block Engine
Part #10103AC880

*Please note OEM Motors have a 3-5 business day lead time before shipping.

New Subaru OEM EJ255 Short Block Engine Part #10103AC880 is a Bone Stock Brand New Genuine OEM fully assembled Short Block. Contrary to public opinion, you can safely make up to 400whp/480bhp on an OEM EJ25 short block with proper maintenance and a solid tune.

This part is an ingredient to our recipe for a reliable Subaru Engine. If you purchase an OEM Block along with our CrawfordSPEC pistons or piston/long rod combo, you can assemble your own Crawford built short block that can handle up to 600whp!

Want a pre-built block ready to go? Check out our Crawford Built WRX Short Block here.

After reading that, you may have had one of many questions or doubts pop in your mind because of all of the opinions floating around on the web along with misleading marketing. Like:
- Subaru engines are prone to fail from the factory
- You need a closed deck block to make high power with an EJ
- I can make 800whp safely with an EJ
- My bearings failed, so I need aftermarket ones. Or: My head gaskets failed so I need aftermarket ones.
The fact is, all of the above statements are not true. Click here to read our blog about what our 30 years of testing Subarus has proven.

What Makes the OEM EJ255 Short Block the Right Foundation

The EJ255 short block is the factory-assembled engine core Subaru used across its turbocharged WRX and select Forester XT and Legacy GT platforms. Part #10103AC880 is built to the same factory tolerances as the day it left Subaru's production line — making it one of the cleanest, most reliable starting points for a rebuild or performance build on the EJ25 platform.

At Crawford Performance, we've spent 30 years testing every combination of EJ upgrades on the street and at the track. Our conclusion: the OEM EJ255 short block is not the weak link. Improper tune, neglected maintenance, and mismatched supporting mods are. Start with a genuine OEM block and build it right the first time.

EJ255 vs. EJ257 — Which Short Block Do You Need?

The EJ255 and EJ257 are closely related but serve different applications:

• EJ255 — the turbocharged block used in the WRX (2002–2014) and select Forester XT / Legacy GT / Outback XT models. Part #10103AC880.
• EJ257 — the STI-spec block with a larger bore and higher-output internals. Used in the WRX STI (2004–2021). View the OEM EJ257 Short Block here — Part #10103AC870.

If you're unsure which block your vehicle uses, check your VIN or contact our team before ordering.

Compatible Vehicles

Part #10103AC880 is a direct-fit OEM assembly for the following vehicles:

• Subaru WRX (2002–2014)
• Subaru Forester XT (2004–2008)
• Subaru Legacy GT (2005–2009)
• Subaru Outback XT (2005–2009)

Want to understand exactly what's inside this assembly and when an OEM block is the right call versus a built option? Read our EJ257 Short Block Guide — it covers the full EJ25 platform, compatibility, and power limits in detail.