This RWD-Swapped 1999 Pontiac Grand Prix Is a DIY GTO With a Five-Speed Manual
Knowing that it’s rear-wheel-drive completely changes how you feel about its looks, too.
Pontiac's final rear-wheel-drive V8 coupe, the GTO, was never as popular as the classic it was named after. While brilliant by all accounts, it's now a rarity, and sometimes a pricey one at that. Fortunately, if you can't afford a GTO, you can apparently just make your own out of a Pontiac Grand Prix, and it costs less than half as much if you do it yourself.
This DIY GTO was constructed by Tyler Pitman, whom I last spoke to about his GM-built Chevy "Feretta" prototype with its unusual Isuzu V8. As the son of a master mechanic, Pitman learned how to modify on a budget by walking through junkyards and seeing what fit. A while back, he used this skill to build his first rear-drive Pontiac Grand Prix, which he described as "a complete mess." But he resolved to revisit the concept and do it better. Last December, when Pitman found a 1999 Grand Prix with a bad transmission for $500, he knew the time had come.
From having seen the underside of countless cars in his day, Pitman used visual memory to guess which parts might work. That began with the rear axle, whose suspension design made switching to another GM axle tricky. He figured out that a last-gen Ford Mustang (S550) would be relatively close, so he bought a rolled 2017 off Copart to pilfer its rear subframe, differential, and suspension. He adapted these using custom mounts and brackets for springs before reinforcing the rear floor and frame rails to make sure the Pontiac wouldn't crumple.
Moving forward, Pitman used a custom driveshaft to link to a five-speed Aisin AR-5 manual transmission from a Chevy Colorado. Using a clutch he bought off Amazon and a custom bell housing adapter, he affixed them to the 5.3-liter, all-aluminum V8 out of a 2009 Suburban. Cramming them all in required much more custom work, from fabricating a transmission tunnel to pushing the firewall back six inches and making mounts for all the new guts. The extra effort means the Pontiac's weight distribution is on point, though.
So is its ability to spin its tires, as the 5.3-liter Vortec was modded on the cheap. It has a hotter cam, eBay headers and a cheap turbo, plus a full three-inch exhaust. The fueling and intake are from an LS1, while the whole thing runs on a modified wiring harness and ECU from a 2008 Tahoe. Pitman tuned it himself, of course. (The radiator is a dual-row unit made for the Mazda Miata, and the aluminum oil pan is from Amazon, in case you wanted to know.)
Because the firewall was relocated, the interior had to be redone, using the dashboard, center console, and door cards from a 2016 Chevrolet Camaro. The seats came from a 2006 Grand Prix GXP, while the pedal box is a third-party floor-mounted setup that actuates Wilwood master cylinders.
Knowing what's been done to this otherwise pathetic Pontiac (my dad had one, I can say it) transforms one's perspective on the shape entirely. Instead of being some ill-considered, overweight coupe, the Grand Prix now looks worthy of its name, and of crashing any GM meet on the planet. I'd give it Best In Show over almost anything GM itself has made—almost anything.
Best of all, while commissioning this car from a shop might cost tens of thousands, Pitman says he's in for less than $8,000. That includes the car, the engine, all the aftermarket parts, and fabrication materials. Pitman said he wants his Pontiac to show people that "everyone can believe in themselves to create something."
"I am the type of guy that likes to see others think outside of the box and do things different," Pitman said. "Anything is possible. It's just up to you to make it happen."
Pitman's build also exemplifies how car modding culture is moving on from the cars of the 1980s and '90s, and toward the cars of the 2000s. Like the AMG V8-swapped Mercedes C320 Sportcoupe I drove last month, both are V8 bruisers built on a budget because their creators were willing to blaze new trails. As the sun sets on the Radwood renaissance, another rises on the cars that followed them—and on new horizons for cheap fun.
Got a tip or question for the author? You can reach them here: james@thedrive.com
