Looking to upgrade your 2003–2008 Honda Civic Si with a more powerful, torque-rich engine? This JDM K24A RBB-2 high-compression long-block engine is the perfect performance replacement for your worn or aging K20A engine. Built for enthusiasts who demand more low-end grunt and high-RPM breathing, this K-series long block offers factory Honda reliability with a serious performance edge.

This long block features the RBB-2 cylinder head and 3-lobe i-VTEC camshaft, providing full VTEC engagement on both intake and exhaust valves. The high compression pistons give this engine an aggressive edge, making it an excellent platform for naturally aspirated builds or forced induction. Compared to the K20A, the K24A delivers more torque and a broader powerband while maintaining compatibility with many stock components and aftermarket K-swap parts.

As a long block, this engine includes the cylinder head, block, internals, and valve cover – ready to accept your K20 intake manifold, sensors, accessories, and ECU setup. Ideal for Civic Si FG2/EP3 owners looking to swap or upgrade without starting from scratch.

All engines from J-Spec Auto Sports are compression-tested, thoroughly inspected, and verified for quality before shipping. Sourced directly from Japan, this low-mileage JDM motor is backed by our 90-day startup warranty, giving you peace of mind on your next build or replacement project.

If you’re serious about upgrading your Civic Si with more power, durability, and VTEC performance, this K24A RBB-2 long block is the best OEM+ solution on the market.

🔧 Key Features:

• JDM Honda K24A RBB-3 2.4L High Compression Long Block

• 3-Lobe VTEC Camshaft & RBB Cylinder Head

• Direct Upgrade Over K20A in 2003–2008 Civic Si

• Compression Tested – Low Mileage from Japan

• Ready for K-Series Swap or Performance Build

• 90-Day Startup Warranty Included