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6223 - Brad Hill Edition Full Mod Zenoah 4 Bolt 28.5cc G290RC Engine - Billet Crankcase

Availability: In stock


Quick Overview

This engine is specifically built and tuned for oval racing. 

Engine compatibility chart

6223 - Brad Hill Edition Full Mod Zenoah 4 Bolt 28.5cc G290RC Engine - Billet Crankcase

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This was our premier oval racing engine. As racing and cars have evolved we've been asked for a more powerful oval racing engine and we've answered with the signature series 30.5cc. We now recommend the 28.5cc version for new racers as this engine has less torque. 

This engine was developed with Brad Hill specifically for oval racing. We went through quite a few prototypes and displacements before coming up this engine. It offers a great balance of torque and rpm's and has proven to be a dominate force on the track. Check out Bodies-by-hill facebook page for custom built top of the line late model bodies. or email 


The following modifications have been done. Just like the rest of our engines this is cnc ported and comes standard with a billet crankcase.
1. Deck cylinder to raise compression without using a thinner cylinder gasket
2. Reshape piston
3. Lighten piston
4. Relieve piston to prevent seizes 
5. Modify intake port for better flow
6. Adjust intake duration to our specs
7. Resurface all ports
8. Modify transfer ports for better flow
9. Enlarge and reshape exhaust port
10. Adjust exhaust duration to our specs
11. Remove stock crank and install stuffed crank
12. Install all new gaskets and c-clips when engine is assembled
13. Re-bevel all porting and stock bevels to prevent damage to the piston and/or cylinder

This engine now comes with a TR/OBR billet crankcase at no extra cost. Every long block or engine is now CNC ported and hand finished. CNC porting and hand finishing is all done in-house by the OBR staff. We do not contract out any of our porting so every engine is modified to our exact specifications. We are able to offer higher accuracy this way as well as more power. Our CNC machine has allowed us to take our porting to the next level due to us being able to do cylinder work that is not possible to do by hand.

Additional Information

Manufacture Zenoah Ported by OBR
Sale Price No

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