12.3 Holley Pro Dash

Brand New Holley 12.3 Pro Dash. We've got a few in stock. All are brand new, and in an unopened box. 

🔵 Blue Dot: Brand new, and/or possibly only open-box items that are ready to roll. Original packaging might not make the cut, but the quality is spot-on. Save up to 25% off retail.

Holley Dash FAQ – Buick Grand National

1. Does Watts Performance offer a custom Holley Dash layout?

Yes! When you purchase your Holley Dash from us, we’ll set you up with the exclusive Watts Performance Custom Layout—for free. Our layout is designed specifically for Turbo Buick performance, giving you a clean, easy-to-read display with all the vital data you need.

This is an incentive only available to customers who buy through Watts Performance, ensuring you get the best setup right out of the box.

2. Can I install a Holley Dash with my stock Grand National ECU?

No. The Holley Dash will not work with the stock Grand National ECM. You’ll need a Holley ECU and the correct Holley EFI wire harness to integrate the dash properly. This setup ensures full functionality and allows for real-time data monitoring and customization.

3. What’s needed to install the Holley Dash?

To run a Holley Dash in your Grand National, you will need:

• Holley ECU (Terminator X, HP, or Dominator)
• Holley EFI Main Harness
• Dash Power and Data Harness

This setup replaces the factory ECM and allows you to display critical engine data in a modern digital format.

4. How do I mount the Holley Dash in a Grand National?

At this time, Watts Performance Solutions has not finalized our custom mounting solution. However, there are vendors that offer dash bezels, mounting plates, and plug-and-play wiring solutions specifically designed for the Grand National. Be sure to choose a setup that fits your needs and provides a clean, factory-like appearance.

5. Does the Holley Dash come with a bezel or mounting plate?

No, the dash itself does not come with a mounting bezel or plate. If you're looking for a bolt-in solution, there are aftermarket vendors offering complete bezel and mounting kits designed specifically for the Grand National. These kits provide a professional finish and make installation much easier.

6. Can I keep my stock gauges working with the Holley Dash?

Yes, you can technically keep your stock gauges, but we recommend removing them for a cleaner, modern look. The Holley Dash replaces all stock gauge functions—including speed, RPM, boost, and coolant temp—so keeping the factory cluster is usually unnecessary. If you want a more OEM+ setup, you can run both, but for a fully integrated experience, we suggest going all-in on the Holley system.

7. Can Watts Performance Solutions install my Holley Dash?

Yes! We offer Holley ECU conversions that include dash installation, wiring, and tuning. If you're upgrading to a Holley system and need expert installation, reach out to discuss your project.

8. What’s the advantage of running a Holley Dash in my Grand National?

Upgrading to a Holley Dash offers several benefits, including:
✅ Real-time data monitoring
✅ Custom gauge layouts
✅ Improved sensor accuracy
✅ Logging and tuning capability
✅ Clean, modern display