When an engine reaches a point and it is no longer to produce the power needed, it has to be rebuilt. There are two different routes to go when you go to rebuild and engine. You can what they call “blueprint” and engine. When blueprinting an engine you are redoing the engine so that it goes back to factory correct engine. That means that the engine is going to produce the same amount of horsepower and torque as it did when it left the factory.
The other more popular option with Gearheads is to take the worn out engine and build it better. This requires tools and a shop to accomplish. From engine hoists to exhaust systems and organization like tool boxes and shop cabinets. With some upgrades, most engines can produce more power and torque then originally came from factory. That could be as simple as a new intake or if your vehicle uses it, carburetor. But if you really get deeper into the engine, you can change almost everything about the engine to optimize power output.