Less head clearance
- Less space for combustion
- More compression
- Advances ignition timing
- More power, especially at high RPM
More head clearance
- Larger space for combustion
- Less compression
- Delays ignition timing
- Less power

Gear Ratio Calculator
Dial in your pinion and spur in seconds — free, with rollout and FDR.
Learn how head clearance affects the performance of your RC car's nitro engine
Less head clearance
More head clearance
Never Forget Maintenance Again
Track diff oil, shock rebuilds, and every job your car needs to stay running right.