This '64 GTO is custom-built...
This '64 GTO is custom-built for road racing and with one thought: To go as fast as you can, and as safely as you can.
Don Stellhorn, a 37-year-old technical sales representative with Street Legal Performance (SLP) in Toms River, New Jersey, says he has been a Pontiac fan since birth, literally. His father, Don Sr., drove him home from the hospital in a '64 GTO hardtop optioned with Tri-Power, four-speed, and Marimba Red exterior. From 1965-1968, his father raced the GTO in the New Jersey Field Trials Association, and the combination of Pontiacs and racing were taught to Don from his earliest days. When he was 13, Don's father helped him buy his first vehicle and it was no coincidence that it was a '64 GTO. After it was totaled in a road course accident in 1998, Don decided to rebuild the GTO to a whole different level.
The GTO
Don bought his '64 GTO in 1984. "It was a post coupe in black primer with no carpet, seats that weren't bolted down, and a Turbo 400 auto trans that didn't shift out of First gear. It was one step away from the crusher, but the frame was good and the price was only $1,100. So we purchased it and the fun began," Don says.
Don Stellhorn is the proud...
Don Stellhorn is the proud owner of this one-of-a-kind '64 GTO. Hot Rod magazine calls it "The baddest looking GTO ever built."
In the early '90s, he was allured by an advertisement in Hot Rod magazine from H-O Racing Specialties that claimed, "Goat Eats Porsche." Don was hooked. He bought every high-performance suspension part he could get his hands on and began road racing and campaigning his GTO in events throughout the second half of the decade. In 1998, disaster struck at a track speed of 135 mph; Don was unable to slow the GTO down enough to navigate a turn and totaled it. Unwilling to give up his first Pontiac, he quickly envisioned a plan to bring the GTO back from the dead.
Chassis And Suspension
To create a GTO road racer capable of extreme speed and handling, Don began with a nearly-clean-sheet-of-paper design for the chassis and suspension. "I started with a bare '64 GTO convertible frame and replaced the rear over-the-axle rails. I then designed a custom three-link rear suspension. The lower control arms are 40 inches in length and run parallel to the driveshaft. They're attached to a custom Ford 9-inch rear axle with 1.0-degree negative camber NASCAR hubs. I used an adjustable upper-third link to fine-tune the pinion angle, which is currently set at 2.5-degrees negative," he says. To center the rear, Don designed a Watts link. The end links and the main unit are adjustable to increase or decrease the rear roll center. To complete the rear suspension, he installed Aldan Eagle double-adjustable road race shocks with Hyperco 16 spring-rate coilovers and a 0.875-inch sway bar with adjustable end links.
A NASCAR-style chassis was...
A NASCAR-style chassis was built by Don from 13/4-inch DOM 0.090 steel tubing. It leaves just enough room for the 440ci Pontiac engine.
Don found the design of the front suspension more difficult. He removed all of the factory suspension mounting locations and completely boxed in the frame. With the help of a computer program, he plotted out the suspension locations and graphed the x and y axis of the caster, camber, and bumpsteer. He said he had concerns regarding suspension bind and it was important to him to have smooth suspension movement. "A stiff suspension is only good for slow-speed handling," Don explains. "I wanted the car's suspension to move because when the wheel is compressed, the suspension will increase negative camber and the tire will continue to lay flat on the ground. In turn, I will have a better handling car and more positive feel."
He fabricated suspension mounting points and installed homemade tubular lower control arms, AFCO upper control arms, and Sweet Steering spindles. Don made his own centerlink and equalized the tie-rod mounting locations to give the car better bumpsteer rebound. He also shortened the steering arms to clear the very wide offset front wheels. Finally, he installed a 1.25-inch Shroeder Racing sway bar with custom-made torsion arms pressed with mono-ball Heim joint endlinks (front) and greaseable steel bushings (rear).
 The cockpit is built for safety...  The cockpit is built for safety and comfort. Door bars are bent away from the driver to give more room while driving on the track. |  The GTO's frame sits 31/2...  The GTO's frame sits 31/2 inches off the ground and the front chin spoiler only 3 inches off the ground. This design forces air around the vehicle instead of underneath it and allows the GTO to be stable at high speeds. |  The Pontiac engine is mounted...  The Pontiac engine is mounted six inches back from its factory location, which gives this GTO a 50/50 front/rear weight distribution. |