Talk to a performance expert

615.446.6807

mon-thurs 9-5 cst

  1. Home
  2. Engines
  3. Tillotson Engines
  4. Tillotson 268R Engine
  5. Tillotson 268R Engines & Kits
  6. Tillotson 268R Engine Kits
  7. EC 268R 4-Cycle Racing Engine Bottom End Kit without Tank Mounts
EC 268R 4-Cycle Racing Engine Bottom End Kit without Tank Mounts
Complete Exploded View of the EC 268R Short block
Write a Review

EC 268R 4-Cycle Racing Engine Bottom End Kit without Tank Mounts

Part Number: 268R-KIT
Online Price: $684.99
Phone Order Price:$699.99
You Save:$15.00(2%)
EC 268R Bottom-End Kit – 268cc Racing Engine Short Block for Tillotson, Clone, and Mini Bike Applications
Questions about this item? Ask here.
Availability: Out of Stock.

Description

EC 268R 4-Cycle Racing Engine Bottom-End Kit - Build Bigger. Race Harder. Introducing the EC 268R.


EC Carburetors proudly presents the NEW EC 268R Bottom-End Kit—our latest innovation in big-bore, high-performance Tillotson engine packages for racing go-karts and mini bikes.


Building on the success of our 3-inch (76mm) block kits, the 268R introduces a 59mm stroker crankshaft to achieve a true 268cc (267.65cc / 16.33ci) displacement. This powerful short-block platform is designed for racers seeking greater torque, higher RPM potential, and exceptional durability—at an affordable price.


Designed for Performance and Compatibility

The 268R shares the same block and piston as our 263R kit, but pairs them with a longer 59mm crankshaft and our in-house engineered 8275 forged connecting rod, also used in the 228R engine series. If you're already running a 3-inch Tillotson block or a 263R build, you can upgrade to the 268R by simply swapping in the new crankshaft and rod.


The 59mm stroke places the piston .005"–.010" in the hole, offering extra piston-to-valve clearance—ideal for aggressive camshaft profiles. Despite this deeper piston position, the increased displacement helps maintain strong compression ratios and power output.


What’s Included in the EC 268R Kit:

- Tillotson 76mm Reinforced Block (No Tank Mounts)
Purpose-built for endurance and sprint racing. This block is thicker and stronger than standard clone blocks, reducing flex, distortion, and blow-by. It’s one of the largest bore sizes available in a factory block.

- 76mm Lightweight Hypereutectic Piston
A racing-grade slipper-skirt piston made from high-silicon aluminum alloy. Offers tighter thermal expansion tolerances and reduced rotating mass. Features a shorter compression height, smaller wrist pin, and greater rod clearance—perfect for stroker builds.

- 59mm (2.3228") Stroker Crankshaft
One of the first 59mm stock-format cranks in the clone market. Only .022" longer than common aftermarket billet cranks but at a fraction of the cost. Fits all Honda-clone flywheels (does not fit Predator 212 flywheels).

- EC 8275 Forged Connecting Rod (3.454")
Designed in-house for added stroke clearance and bigger cam compatibility. Positions the piston slightly in the hole to enhance valve clearance. Manufactured from premium forged aluminum for strength and reliability.

- Stock Sidecover
Factory-style compatibility with proven sealing and durability.

- Stock Tappets
Reliable and compatible with most common clone-style camshafts.

- Complete Hardware & Gasket Set
All necessary components to assemble the short block.


What’s Not Included:

- Camshaft

- Pushrods (Chromoly pushrods are highly recommended for all racing applications)

- Head Gasket


Additional Notes:

- This is a partial short block kit designed for racers who want to add their own top-end components, such as cylinder heads, carburetors, rockers, and ignition systems.


- EC offers a variety of add-ons and upgrades if you’d like to complete your build through us.


- This engine kit is intended for racing use only. Final assembly and tuning are the builder's responsibility.

No warranty is provided for this racing product.


Why Choose the EC 268R Kit?

- Proven platform based on the trusted 263R and 228R engines.

- Delivers high displacement at a lower cost than billet crank setups.

- Modular design supports upgrades and customization.

- Designed by racers, for racers.


Ready to build your next race-winning engine? The EC 268R Bottom-End Kit is the foundation for serious performance.

FAQ

Does the kit require any machining or clearancing?

No machining or clearancing is required for the included components. The cylinder has already been sleeved, bored, and honed for proper assembly. However, depending on your choice of camshaft, you may need to clearance the crankcase for the compression release mechanism or large cam lobes.


If you plan to use a copper head gasket, we recommend having your cylinder head O-ringed to ensure proper sealing under high compression and temperature conditions.


Do you assemble the 268R short block?

No, we do not pre-assemble the 268R short block. Since this kit supports a wide range of custom configurations—including different camshafts, flywheels, and cylinder heads—pre-assembly would require disassembly to make those specific adjustments.

Selling it as an unassembled kit keeps costs down and gives experienced builders full control over their final setup.


Do you build complete 263R or other custom engines?

We do not offer complete versions of the 263R or perform custom one-off engine builds. However, we do occasionally have fully assembled engines available for purchase on our website, such as the 228R and variations of the 223 Wildcatand 236R engines.


How much horsepower can this kit produce?

Horsepower estimates without certified dyno data (e.g., SAE testing) are speculative at best. However, here’s a realistic way to frame expectations based on industry benchmarks:

- In the golden era of performance engines (1960s–70s), 1 horsepower per cubic inch was the standard for a strong, high-performance build. At 16.3 cubic inches, this would equate to approximately 16 horsepower—which is a very stout small-engine build.


- Extremely well-built Pro Stock-style engines from that same era could achieve up to 2 horsepower per cubic inch—about 32 HP in this case. These builds are rare and require extensive custom work.


- Modern Pro Stock engines can exceed 2.5 to 3 HP per cubic inch, but reaching 40+ horsepower from an air-cooled, small-displacement engine like this—with limited development and budget constraints—is unrealistic.


Bottom line: With the right combination of cam, carburetion, porting, and tuning, the EC 268R kit offers serious performance potential—but real-world results will vary based on build quality and component choices.

Related Items

EC 263R 76mm x 58mm Rotating Assembly
EC 263R 76mm x 58mm Rotating Assembly
$274.99
Out of Stock.
EC 263R 4-Cycle Racing Engine Bottom End Kit with Tank Mounts
EC 263R 4-Cycle Racing Engine Bottom End Kit with Tank Mounts
$679.99
Out of Stock.
EC 263R 4-Cycle Racing Engine Bottom End Kit without Tank Mounts
EC 263R 4-Cycle Racing Engine Bottom End Kit without Tank Mounts
$659.99
Out of Stock.
EC 268R 76mm x 59mm Rotating Assembly
EC 268R 76mm x 59mm Rotating Assembly
$299.99
Out of Stock.

Recently Viewed Items

Logo