How much horsepower does a GM 4.3 liter engine have?

The horsepower of a GM 4.3L engine varies significantly depending on the year of manufacture, the specific application (truck, van, boat, etc.), and whether it's naturally aspirated or has modifications. There's no single answer. Output ranged from roughly 160 hp to well over 200 hp in various configurations over the years. You'll need to specify the year and model of the vehicle or engine to get a precise horsepower rating.