To "change" a 350 fuel injection system to a carburetor system would be a major engine conversion, requiring significant modifications and new parts. This is not a simple swap and is beyond the scope of a simple answer. It would involve:
* Replacing the entire fuel delivery system: This includes removing the fuel injectors, fuel rail, fuel pump (likely), and all associated wiring and sensors. You would need to install a new carburetor, fuel pump (likely a mechanical pump instead of an electric one), fuel lines, and potentially a new intake manifold designed for a carburetor.
* Modifying or replacing the intake manifold: Fuel injection manifolds are designed to distribute fuel to injectors; carburetor manifolds have a single large port for the carburetor to sit on.
* Addressing ignition timing: The ignition timing might need adjustments as carburetors and fuel injection systems have different fuel delivery characteristics that influence optimal spark timing.
* Addressing the Engine Control Unit (ECU): The ECU controls the fuel injection system and will need to be disconnected and bypassed.
* Vacuum system changes: Carburetors use vacuum for several functions (brake booster, distributor advance, etc.). The vacuum system would need to be adapted to work with a carburetor.
* Emissions compliance: Converting to a carburetor will likely render the vehicle non-compliant with modern emissions regulations.
In short, changing a fuel-injected 350 to carburetor operation is a complex, time-consuming, and expensive project requiring significant mechanical and electrical expertise. It's not something a novice mechanic should attempt. It's far more likely to be cheaper and easier to just find a different 350 engine that already uses a carburetor if that's your preference.
