The maximum horsepower a 350 4-bolt block can handle depends on several factors, including the specific components used, the quality of the block, the intended use of the engine, and the level of modifications or upgrades applied.
In general, a stock 350 4-bolt block from a reputable manufacturer can handle approximately 400 to 450 horsepower reliably. However, it's important to note that pushing the engine to its limits or beyond may increase the risk of failure or damage.
If you plan to exceed these power levels, it is recommended to reinforce the block with additional measures such as using stronger aftermarket components, reinforcing the bottom end, upgrading the rotating assembly, and improving cooling and lubrication systems. These modifications can significantly increase the engine's power handling capabilities.
It's also crucial to consider factors such as the transmission, drivetrain, and other supporting components, as they need to be able to handle the increased power and torque as well.
If you have specific performance goals in mind or are considering significant modifications to your engine, it is best to consult with a knowledgeable engine builder or a performance specialist who can provide you with more accurate information and guidance based on your specific requirements.