(Image/Summit Racing – Todd Biss Productions)

Remember how the high performance community was shocked when the track-focused 2014 Camaro Z/28 broke cover with massive 305/30ZR19 tires at all four corners? Mike Guess must’ve thought that was only a good place to start.

(Image/Summit Racing – Todd Biss Productions)

His 1964 GTO—the first year for Pontiac’s groundbreaking muscle car—is packing absurdly wide 315/30ZR18s at both ends, plus a race-ready chassis, a 630 hp LS mill, and much, much more. Every bit as impressive as the radical running gear is the immaculate, stock-appearing body dressed in retina-searing Viper Red paint and a custom interior that’s equipped for hot lapping or comfy cruising.

(Image/Summit Racing – Todd Biss Productions)

Huge BFGoodrich g-Force Rival tires. Three-piece Forgeline wheels. StopTech brakes. A Ford 9 in. floater rear end. Double-adjustable RideTech coilovers. A Speedtech ExtReme chassis to tie it all together. Mike’s GTO has a spec sheet that reads like a road racer’s letter to Santa, and it all fits neatly under a Best of Show-winning body.

(Image/Summit Racing – Todd Biss Productions)

The build started with a scrap car, and Mike intended to keep it simple with a few suspension upgrades—a quest for “modern conveniences, more horsepower, and better handling,” as he put it. But that wasn’t enough. “With the original frame and the engine I wanted to use, I realized it wasn’t going to win any autocrosses,” Mike said.

(Image/Summit Racing – Todd Biss Productions)

For some, it all might seem like too much. But it’s just right for a man who’s a lifelong GTO enthusiast, restorer, drag racer, and now, autocrosser. As owner of Guess Motors, a Buick, Ford, GMC dealership in Carrollton, Ohio, Mike’s love of GTOs was almost a foregone conclusion. His grandfather opened the Pontiac store in 1933, and both he and his father grew up in the business, selling Pontiacs until the brand was shuttered in 2010. “The first car I ever noticed when I was a kid was a GTO,” Mike said. He also caught the drag racing bug at an early age, watching Larry “Doc” Dixon race the Knafel Pontiac 1966 GTO at Magnolia Dragway in Magnolia, Ohio. “I told my dad, ‘I’m going to do that someday.’ When I turned 18, I started racing,” Mike said.

(Image/Summit Racing – Todd Biss Productions)

For many years, he drag raced a highly modified, 455-powered 1965 GTO, restored and showed 1960s GTOs, and has owned “many, many” other GTOs. This is Mike’s sixth 1964 GTO, and was languishing in his junkyard with very little of the original car left. Work began in 2012, and while Mike was very experienced restoring the iconic Pontiac muscle cars, a pro touring-style build was out of his wheelhouse. With that in mind, the GTO was sent to a shop in Michigan. From there, work progressed slowly, and it started to become apparent that a pro touring build might be outside of that shop’s comfort zone, too.

(Image/Summit Racing – Todd Biss Productions)

At the end of 2016, with progress stalled, the GTO was sent off to Ross Gregory’s Marquette Classics in Ionia, Michigan, initially for some electrical work. With the help of painter Dan Farr and technician Bill Swain (two guys, as Ross puts it, “I trust as much as I trust myself”), the three-person shop does nearly everything in-house. And the decision to move the project to a new shop ended up being critical, as Mike’s plans for the car became more extensive.

(Image/Summit Racing – Todd Biss Productions)

Mike had gotten his feet wet in autocross with a Ford Focus RS—a highly capable vehicle, even bone stock. He wanted the GTO to be an even more potent track weapon, a tall order for a 50-plus-year-old platform. A visit to a Ron Sutton Race Technology chassis workshop confirmed his suspicions. “I showed Ron what I was building, with all the aftermarket parts on the stock frame, and asked if I could win with it. He said, ‘If you can drive, you have 25% chance of winning. If you can’t drive, you won’t win.’ I didn’t want to build a car that only gave me a 25% chance of winning,” Mike said.

(Image/Summit Racing – Todd Biss Productions)

That conversation led Mike to choose a Speedtech Performance ExtReme Chassis; a rigid, fully boxed unit featuring double A-arm front suspension with forged aluminum spindles and a unique torque arm rear suspension. It mounted to the Pontiac body without issue, and Speedtech provided wheel specifications to fit the massive BFGs within the confines of the stock fenders. Making certain they didn’t rub was up to Ross and his crew. They created stock-looking inner fenders that were widened approximately 4-3/4 in. up front, and just a bit less in the rear. “That’s what Mike wanted, and we were dumb enough to say we could do it,” Ross laughed. The result? They checked “about a thousand times,” he said, and the impossibly wide front tires don’t rub—ever.

(Image/Summit Racing – Todd Biss Productions)

A counterpoint to the stiffly suspended chassis and stout powertrain is the comfy retro-modern interior. The seats are upholstered in two-tone custom, handsewn leather, steering is handled by an original wood-rimmed GTO wheel, and the stock-appearing dash houses Dakota Digital gauges. Even the RideTech TigerCage is a nod to comfort and practicality. The door bars can be removed when not needed, and the harness bar also comes out when it’s time to take the grandkids for a spin. Underneath it all is an obsessive amount of Dynamat insulation—even in the trunk, which houses a full-size spare.

(Image/Summit Racing – Todd Biss Productions)

The 630 hp Mast Motorsports Black Label LS, backed up by a TREMEC T-56 Magnum, is more than sufficient to motivate the 3,800 pound Pontiac. Of course, like any car guy, Mike would like a bit more. Forced induction is the obvious solution, but a Roots-type blower would be a quarter to a half inch too tall, and Mike isn’t about to modify the rare, original GTO hood. How about a centrifugal supercharger? “Nah. I just don’t care for the way they look,” Mike said. So the LS will remain naturally aspirated—for now.

(Image/Summit Racing – Todd Biss Productions)

Mike and Ross’ working relationship was key to the finished product. “The communication these two had was unmatched,” Carol, Mike’s wife, said. Ross questioned many of the details Mike specified. For example, he didn’t think painting the engine Pontiac blue was a good idea, and felt the front spoiler would look better with a semi-gloss black finish. “Mike said it’d look better shiny. I said, ‘I don’t know,’ but that’s another one where he was right,” Ross admitted. “Often, you can kind of steer a customer. But Mike had a very clear vision. I’d say, ‘Are you sure?’ he’d say, ‘Yes, Ross,’ and he was right,” he added. This dialog was repeated throughout the build process: the wheel and tire combo…the decision to keep all the bright exterior trim…choosing the “reddest red” paint, as Mike put it.

(Image/Summit Racing – Todd Biss Productions)

The build was finished in May of 2021, and a year later Mike had logged over 900 miles, working out minor issues and collecting awards. The GTO’s days as a pampered show car are numbered, though. It was built to be driven hard, and soon that impossibly perfect Viper Red paint will be facing the possibility of bumps and bruises on the autocross course.

(Image/Summit Racing – Todd Biss Productions)

We can’t wait to see Mike’s cone-carving classic in action!

The GTO carries a full-size spare for worry-free touring. (Image/Summit Racing – Todd Biss Productions)
Sound-deadening insulation was installed everywhere—even in the beautifully finished trunk. (Image/Summit Racing – Todd Biss Productions)
back seat & roll cage in a 1964 pontiac gto autocross car
The back seat is ready for passengers when Mike removes the harness bar from the RideTech TigerCage. (Image/Summit Racing – Todd Biss Productions)
The 630 hp Mast Motorsports LS was finished in Pontiac blue. Ultimate Headers 321 Stainless Steel headers handle exhaust duty and add some underhood eye candy. (Image/Summit Racing – Todd Biss Productions)

Mike & Carol Guess’s 1964 Pontiac GTO Fast Specs

Body & Chassis

Wheels & Tires

Engine & Transmission

Air, Fuel & Electrical



  • Paint and bodywork by Marquette Classics, Ionia, MI
  • PPG Viper Red paint
  • Original stainless trim and grilles restored by Bruce Dell, Hubbard, OH
  • Dapper Lighting LED halo headlamps



  • GTO Association of America 2021 Convention, Concours Gold Level Award
  • 2021 Pontiac Nationals, Custom GTO class winner
  • LS Fest East 2021, Best of Show
  • 2021 Timken Family Cancer Center Car Show, Best of Show
  • 39th Annual Attwood Area Fall Festival Car Show, Best of Show

Special Thanks

Ross Gregory, Dan Farr, and Bill Swain at Marquette Classics; Ron Sutton Race Technology; the late Bob Shaffer; Bob Ammond of AAA Welding; Brian Turner at Dyno Tune Motorsports; John Wagner at Custom Leather and Canvas; Roger Maniscalco at Speedtech Performance; and my friends Tom Bole and Ken Moravek for helping along the way. Most importantly, I would like to thank my wife, Carol, for being patient with me as this dream became a reality.

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Author: Aaron Dolezal

Aaron spent over 13 years as a Porsche and Audi technician before trading his wrenches for a keyboard to write for Summit Racing. Aaron enjoys being outdoorsy with his girlfriend and their dog, arguing with their two cats, and thinking about working on the 1991 Miata and old motorcycles in the garage.