New Subaru OEM EJ257 Short Block Engine
Part #10103AC870

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

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 options by clicking 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 all about what our nearly 30 years of testing Subaru's has proven.

What Makes the OEM EJ257 Short Block the Right Foundation

The EJ257 short block is the engine assembly Subaru engineered specifically for the WRX STI — and for good reason. The factory block, crank, rods, and pistons are precision-matched from the factory floor, making Part #10103AC870 one of the cleanest starting points for a reliable STI rebuild or performance build.

At Crawford Performance, we've spent nearly 30 years pushing these engines at the track and on the street. Our conclusion: the OEM EJ257 short block is not the weak link — improper tune, neglected maintenance, and mismatched supporting mods are. Start with a fresh OEM block, build smart, and this engine will reward you.

Compatible Vehicles

Part #10103AC870 is a direct-fit OEM assembly for the following vehicles:

• Subaru WRX STI (2004–2021)
• Subaru WRX STI Hatchback (2008–2014)
• Subaru Forester XT (2004–2013)
• Subaru Legacy GT (2005–2012)
• Subaru Outback XT (2005–2009)

Not sure if the EJ257 is the right block for your build? Read our EJ257 Short Block Guide — it covers compatibility, what's inside the assembly, and when an OEM block is the right call versus a built option

Want it better than stock? The Crawford Essentials EJ257 short block — this same OEM block with every bearing upgraded by Crawford.

Step four of our reliability recipe is an Air/Oil Separator. Here's why every Subaru engine needs one.

EJ255 or EJ257? Which block is right for your build.

Read: What actually kills EJ motors.

Our motors are built to order. What that actually means.