Step-by-step: Installing a Holley 850 Ultra Double Pumper on Your Pontiac 455

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Installing a Holley 850 Ultra Double Pumper on your Pontiac 455 can significantly enhance performance. This guide provides a detailed, step-by-step approach to ensure a successful installation.

Tools and Materials Needed

  • Holley 850 Ultra Double Pumper carburetor
  • Socket set
  • Wrench set
  • Flathead screwdriver
  • Phillips screwdriver
  • Fuel line wrench
  • Gasket scraper
  • New carburetor gasket
  • Throttle return spring
  • Safety glasses

Preparation Steps

Before starting the installation, it’s essential to prepare your workspace and the vehicle. Follow these steps:

  • Ensure the engine is cool to avoid burns.
  • Disconnect the negative battery terminal to prevent electrical issues.
  • Remove the air cleaner assembly from the existing carburetor.
  • Take photos of the current setup for reference during reinstallation.

Removing the Old Carburetor

With the preparation complete, you can now remove the old carburetor. Follow these steps carefully:

  • Use the fuel line wrench to disconnect the fuel line from the existing carburetor.
  • Remove the throttle linkage by unscrewing the bolts with a socket or wrench.
  • Unbolt the old carburetor from the intake manifold using a socket set.
  • Carefully lift the old carburetor off the manifold and place it aside.

Preparing the New Holley 850 Ultra Double Pumper

Before installing the new carburetor, ensure it is ready for installation. Follow these steps:

  • Check the new carburetor for any shipping damage.
  • Install the new gasket onto the base of the carburetor.
  • Adjust the float levels according to the manufacturer’s specifications.
  • Ensure the choke is set correctly if applicable.

Installing the Holley 850 Ultra Double Pumper

Now, it’s time to install the new carburetor. Follow these steps for a successful installation:

  • Carefully place the new Holley carburetor onto the intake manifold.
  • Align the bolt holes with the manifold and secure it with bolts.
  • Tighten the bolts in a crisscross pattern to ensure even pressure.
  • Reconnect the throttle linkage to the new carburetor.
  • Attach the fuel line to the new carburetor, ensuring a tight fit.

Finalizing the Installation

After securing the carburetor, it’s important to finalize the installation. Follow these steps:

  • Reconnect the negative battery terminal.
  • Double-check all connections for any leaks or loose fittings.
  • Install the air cleaner assembly back onto the carburetor.
  • Start the engine and let it idle to check for proper operation.

Tuning the Carburetor

Once the installation is complete, tuning the carburetor is essential for optimal performance. Follow these steps:

  • Adjust the idle speed and mixture screws as needed.
  • Test drive the vehicle to assess performance.
  • Make further adjustments based on engine response and performance.

Conclusion

Installing a Holley 850 Ultra Double Pumper on your Pontiac 455 can greatly enhance engine performance. By following these steps carefully, you can ensure a successful installation and tuning process. Enjoy the improved power and responsiveness of your Pontiac!