How much horsepower do a lt1 have with flowmasters?

The LT1 engine, in its factory form, typically produces around 350 to 455 horsepower, depending on the model year and application. Adding Flowmaster exhaust systems can enhance performance by improving exhaust flow, potentially increasing horsepower by an additional 5 to 15 horsepower. However, the exact increase can vary based on the specific setup and tuning. Always consider additional modifications and tuning for optimal results.