How much horse power does the 4.3 Chevy silverado engine have?

The horsepower of a 4.3L Chevy Silverado engine varies depending on the year of manufacture and whether it's a naturally aspirated or forced induction engine (though forced induction was rare on the 4.3L). There's no single answer. You'll need to specify the year of the truck to get a precise answer. Generally, expect to see horsepower figures ranging from roughly 160 to 200 hp for naturally aspirated versions.