Home Car Culture A DIY GTO with a Five-Speed Manual: The RWD-Swapped 1999 Pontiac Grand Prix

A DIY GTO with a Five-Speed Manual: The RWD-Swapped 1999 Pontiac Grand Prix

A DIY GTO with a Five-Speed Manual: The RWD-Swapped 1999 Pontiac Grand Prix

Pontiac GTO fans rejoice! If you’ve always dreamed of owning one but couldn’t afford it, there’s a solution that could cost you less than half the price. Tyler Pitman, a DIY enthusiast and son of a master mechanic, has come up with a brilliant idea to create a rear-wheel-drive, V8-powered Pontiac GTO out of a Pontiac Grand Prix.

Pitman’s journey began with his previous project, a GM-built Chevy “Feretta” prototype with an Isuzu V8 engine. Drawing on his experience and knowledge gained from walking through junkyards, Pitman decided to embark on an ambitious project to build his own rear-wheel-drive Pontiac Grand Prix. Although his first attempt was a bit of a mess, Pitman was determined to improve on the concept.

In December, Pitman stumbled upon a 1999 Pontiac Grand Prix with a faulty transmission for just $500. He saw it as a sign that the time had come to bring his idea to life. Knowing which parts might work, Pitman used his visual memory and decided to incorporate the rear subframe, differential, and suspension from a rolled 2017 Ford Mustang (S550). This required custom mounts and brackets for the springs, as well as reinforcing the rear floor and frame rails to ensure structural integrity.

Moving on to the drivetrain, Pitman opted for a five-speed Aisin AR-5 manual transmission from a Chevy Colorado, connected to a 5.3-liter, all-aluminum V8 engine from a 2009 Suburban. This required extensive custom work, including fabricating a transmission tunnel, pushing the firewall back six inches, and creating mounts for the new components. The extra effort paid off in terms of weight distribution and overall performance.

To give the Pontiac Grand Prix its mean power, Pitman modified the 5.3-liter Vortec engine on a budget. He added a hotter cam, eBay headers, a cheap turbo, and a three-inch exhaust. The fueling and intake system came from an LS1, while the wiring harness and ECU were adapted from a 2008 Tahoe. Pitman even sourced affordable aftermarket parts, such as a dual-row radiator designed for the Mazda Miata and an aluminum oil pan from Amazon.

With the firewall relocated, the interior required a complete makeover. Pitman used the dashboard, center console, and door cards from a 2016 Chevrolet Camaro, while the seats were sourced from a 2006 Grand Prix GXP. He installed a third-party floor-mounted pedal box that actuates Wilwood master cylinders.

The transformation of the Pontiac Grand Prix is impressive. What was once an ill-considered, overweight coupe now looks like a worthy successor to the legendary GTO. Pitman’s build showcases the potential for creativity and resourcefulness, proving that anyone can create something extraordinary. The total cost of the project, including the car, engine, aftermarket parts, and fabrication materials, is less than $8,000—a fraction of what a professional shop might charge.

Pitman’s DIY masterpiece also represents a shift in car modding culture. While enthusiasts have long focused on cars from the ’80s and ’90s, projects like Pitman’s highlight the growing popularity of early 2000s vehicles. With a willingness to push boundaries and think outside the box, builders like Pitman are blazing new trails and uncovering new horizons for cheap fun. As the Radwood era draws to a close, a new wave of car enthusiasts is emerging, ready to embrace the cars that followed and create unique, budget-friendly builds.


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