It's impossible to say without measuring it on a dyno.
If the truck is absolutely 100% factory stock - no mods, no rebuilds, nothing - look up the original HP for that model truck online (try mortec.com).
Then take off 1% of the factory HP for every 10K miles on the engine. (This doesn't really apply to engines under 50K miles, but makes a good estimate for high mileage engines.)
Factory rating is 200 horsepower.
The 350 cubic inch (5.7 liter) pickup engine was factory-rated at 200 horsepower in 1994.
250-290 hp
Chevy didn't make a 350 engine in 2001
A stock 1990 Chevy silverado with a 350 cubic inch, 5.7 liter V8 engine produces 210 horsepower.
350
275
190
Chevy says about 210hp.
Right about 245.
250 to 350 hp depending on what model
The 1972 Chevy 350 has about 270 horsepower stock. This engine can be modified to put out up to about 800 horsepower.