* Power Output: The main difference is horsepower and torque. The standard 4.0L produced less horsepower and torque than the HO version. The exact numbers vary slightly depending on the year and other factors, but the HO consistently delivered a noticeable increase.
* Internal Differences: To achieve the higher output, the HO engine typically featured modifications such as:
* Improved Intake and Exhaust: The HO often had a redesigned intake manifold and a more free-flowing exhaust system, allowing for better breathing and increased airflow.
* Higher Compression Ratio: A slightly higher compression ratio helped squeeze more power from the fuel-air mixture.
* Revised Cam Profile: A different camshaft profile optimized valve timing for better power delivery.
* Electronic Throttle Control: The HO may have transitioned to electronic throttle control (ETC), replacing the older cable-operated throttle.
* Other Potential Differences (Year-Dependent): Some years might see differences in other components like pistons, connecting rods, or even the heads themselves, though these aren't guaranteed across all HO models.
In short, the HO 4.0L in a Jeep Cherokee wasn't a drastically different engine, but a series of refinements to a proven design resulted in a significant bump in power and performance, making it a more desirable option for many Jeep enthusiasts. Always check the specific year and model details, as the precise differences can vary slightly.
