* The type of engine: A 350 small-block Chevrolet V8 will perform very differently than a 350 cubic inch marine engine, or even a different configuration of a Chevy 350.
* Modifications: Has the engine been modified with performance parts (camshaft, intake manifold, carburetor/fuel injection)? Modifications drastically change horsepower and therefore speed.
* Vehicle it's in: The weight of the vehicle, its aerodynamics, gearing, and transmission type all impact how fast the vehicle will go.
A stock 350 Chevy small-block in a car might have a top speed somewhere in the 80-100 mph range, but this is a very rough estimate. A highly modified 350 in a lightweight car could easily exceed 150 mph. Conversely, a 350 in a large, heavy boat might only reach speeds in the low tens of mph.
To get a meaningful answer, you need to specify the *type* of 350 engine and the *application* (what vehicle or machine it's powering).
