Here's why:
* Bolt Pattern: While the bolt pattern *might* be compatible (it depends on the specific 350 intake manifold), it's unlikely to be a direct bolt-on. Many 350 intakes are designed for older, non-Vortec small-block Chevy engines with different port configurations and runner designs. This could lead to significant clearance issues with the Vortec heads.
* Port Matching: The intake ports on a 350 intake and Vortec heads are almost certainly different sizes and shapes. This mismatch will severely restrict airflow, leading to a loss of power, rather than a gain. Significant porting and matching work would be required.
* Fuel Injection: Vortec engines use fuel injection, while some 350 intakes are designed for carburetors. You'd need to adapt your fuel injection system, which is a complex undertaking.
* Throttle Body: The throttle body location and size would be completely incompatible, requiring major modifications or replacement.
In short, using a 350 intake on a 5.7L Vortec engine is a project that's far more trouble than it's worth unless you're a highly experienced engine builder with specialized tools and a clear understanding of airflow dynamics. It's much more practical and efficient to source a properly designed intake manifold specifically for the 5.7L Vortec engine.
