How much horsepower of 16.4 liter?

You can't determine horsepower from engine displacement (16.4 liters in this case) alone. Horsepower is a measure of power output, while displacement is a measure of engine size (the volume of the cylinders). Engines with the same displacement can have vastly different horsepower outputs depending on many factors, including:

* Design: Naturally aspirated, turbocharged, supercharged. Forced induction (turbo/supercharger) dramatically increases horsepower.

* Technology: Advanced fuel injection, variable valve timing, and other technologies all affect power output.

* Tuning: How the engine is tuned (computer programming, etc.) significantly affects horsepower.

* RPM: Horsepower is measured at a specific engine speed (RPM). The same engine will produce different horsepower at different RPMs.

A 16.4-liter engine could produce anywhere from several hundred to over a thousand horsepower depending on these factors. Think of it like this: a small, highly tuned engine might have more horsepower than a larger, less-efficient one.