Building "Hammerhead": A 1450WHP Twin-Turbo 1973 Pontiac Firebird Time Attack Car

The Genesis of Hammerhead

• 💡 The project, nicknamed "Hammerhead," is a 1973 Pontiac Firebird meticulously transformed into a time attack race car by Horizon Motorsports.
• 🎯 The build was initially conceived as a four-month, $20-30,000 track car for learning welding and fabrication skills.
• 🔑 The foundation was an eBay find: a 1973 Trans Am with a title and VIN, serving as the only original part retained, with everything else custom-fabricated.

Powertrain and Performance

• 🚀 Hammerhead boasts 1450 wheel horsepower from a custom LSR engine built by Late Model Engines, featuring twin Garrett G35-1050 turbos.
• ⚙️ A unique setup includes a Corvette torque tube and an Extrac transaxle, capable of handling speeds over 200 mph with different gear sets.
• 🏎️ The engine's central placement is a deliberate choice for optimal weight distribution, achieving 51% rear and 49% front bias.

Chassis and Suspension Engineering

• 🛠️ The custom chassis is constructed from approximately 450 feet of tubing, including a robust halo structure over the driver's area for strength.
• 🏁 Inspired by high-end sports cars, the powertrain, including the transaxle, is designed to drop out the bottom for easier access.
• 🌟 The car features Rainard IndyCar suspension components from 2000-2002, including Ohlins dampers and Hyperco springs, allowing for rapid adjustments.

Aerodynamics and Design Philosophy

• 💨 All major aerodynamic components, such as the splitter and rear wing, are fastened directly to the chassis, ensuring extreme rigidity and performance.
• 🌊 The design incorporates a flat bottom and a massive diffuser to maximize downforce, with the angle drive in the transaxle strategically placed to accommodate this.
• 🎨 The car's name, "Hammerhead," was inspired by its wide front end and shark-like appearance when viewed from below.

Building and Advice

• 📈 The build process involved extensive use of CAD software and 3D printing, leveraging motorsport engineering knowledge gained through formal education.
• ⚠️ A key piece of advice for future builders is to be realistic about budget and timelines, as projects often exceed initial estimates.
• 🗓️ Setting a firm deadline, such as for a show like SEMA, can provide crucial motivation and focus to complete the build.