Cosworth CNC Ported Cylinder Head Set w/ 20007395 Cams

Part #: COS2 20010140


Brand: Cosworth
Head Alteration Required: No
Includes Camshafts: Yes
Machining Required: No
Material: Aluminum
Percent Flow Increase Exhaust: 37.78
Percent Flow Increase Intake: 19.38
QTY: 2
Retainers: Titanium
Springs Included: Yes
Valves Included: Yes
Mfgr. Warranty: No Warranty
Return Policy:

RallySport Guarantee - 30 Days

Items that are covered under the RallySport Guarantee offer a 30 day no questions asked return policy.

RallySport Guarantee items may be returned within 30 days of the original invoice date and must include all the original parts and contents for a refund.

The RallySport Guarantee does not apply to products that have been modified, damaged, misused or abused. All returns require an RMA (Return Merchandise Authorization) Number, and freight charges are strictly non-refundable. For more information regarding our freight refund policy, please refer to our return policy page found HERE.
Not Specified


Cosworth Big Valve Cylinder heads for the Dual AVCS 2008 STI EJ257B engine. Machine Ported for maximum accuracy and performance, complete with larger (+1mm) valves and dual valve springs for maximum flow. Cosworth Big Valve Cylinder heads are the key to high power and unlocking the performance potential in your Subaru engine.

These heads include the S2 version camshafts (20007395) with the correct cam followers included. This is the perfect head/camshaft combination for serious performance and track day use.





  • AnswerQ: 2.8L  kat00f76730 11 months ago

    I have stroker block kit BC 2.8L and GTX3582r turbo just i have stock head its that's head it be good for me ?

    • A: Better flowing heads are going to benefit the vehicle and help it achieve more power, they are definitely beneficial for an aggressive setup like a stroker.

      Nick S. 11 months ago

  • AnswerQ: blocks  nickgo41890 2 years ago

    hi rallysportdirect thinking about purchasing these heads. what short block do you recommend for the best performance with these heads? Thanks Dominic

    • A: If you plan on purchasing heads and block, we HIGHLY suggest to just get the Cosworth Long Block. Reason is that the long block comes assembled, includes cams, buckets, gaskets, ect. Not only do you end up saving money by buying a Cosworth long block vs individual parts, but you also dont need to pay labor to have it all assembled by some of the worlds best engine builders. For more details, please contact us via chat, email or phone so we can better answer your question to suite your individual needs and goals.

      Kirill C. 2 years ago

  • AnswerQ: rev capability?  fatbastard 4 years ago

    up to what RPM range can these heads handle?

    • A: The heads are just a guide for the air to flow. So the RPM would depend on your cams, and oil system set up more then the heads.

      Kirill C. 4 years ago

  • AnswerQ: Heads Flow  LS7Fox 4 years ago

    I'm curious to what these heads flow numbers are and its max lift capabilities.

    • A: The max lift limit of the Cosworth heads out-of- the box is set at 11mm when accounting for valve lash. Max lift with modified castings for clearance around the bucket is set at 12mm. The max lift limit of our valvespring itself is 14mm. Head flow numbers can be sent to you in a chart via email. Please contact your RSD sales rep or email with your inquiry.

      4 years ago

    • A: The Cosworth heads increase exhaust flow by 37.78% and intake flow by 19.38%. The S2 cams included with the heads contain a 10mm exhaust lift and a 10.7mm intake lift.

      paul559b5ed28149810a128b5c51 4 years ago