The season would begin, for the first time in IMSA History, by the 24 Hours of Daytona. It would become a traditional fixture in the ever growing calendar. Peter Gregg and Hurley Haywood won the race in spite of a shunt with a slower car. Michal Keyser, Billy Sprowls and Andres Contreras finished second and Charlie Kemp and Carson Baird took third. It was a Porsche sweep, and the first non-Porsche was the Ferrari 365GTB4 driven by Jon Woodner and Fred Phillips, who won the Group 4 class. Rusty Bond and George Rollin won the GTU class ahead of the Porsche 911 driven by George Drolsom and Bob Nagel.
The 12 Hours of Sebring was to bring a big surprise as BMW won the race after dominating the race. The car driven by Brian Redman-Allan Moffat-Sam Posey and Hans Stuck earned a somewhat easy victory with every works driver at the wheel of the winner. George Dyer and Jacques Bienvenue finished second and John Graves, John O'steen and Dave Helmick third also in a Porsche Carrera RSR. Tony Garcia, Albert Naon and John Freyre, in a Porsche 911 won the GTU class, ahead of George Drolsom and Bob Nagel again taking the class second place.
At Road Atlanta, a brand new car was to later make history in the name of the Dekon Chevrolet Monza. Horst Kwech drove the car, which proved fast out of the box. However, Peter Gregg would not yield his domination so easily, as he won the first heat over Al Holbert and Hurley Haywood. John Greenwood was next. Bob Sharp dominated the GTU class in his Datsun 260Z, Dave Causey finished second. Al Holbert won the second heat over Hurley Haywood and Michael Keyser. Bob Sharp again won the GTU, with Don Parish and John Belperche coming next.
At Laguna Seca, Peter Gregg won the first heat over Hans Stuck in a works BMW 3.0CSL and Elliot Forbes Robinson in a Porsche Carrera RSR. Walt Maas took the GTU victory in a Datsun 260Z over Brad Frisselle and Bob Sharp who drove both Datsun 260Zs. Hans Stuck took his revenge in the second heat and won over Michael Keyser and Elliot Forbes Robinson. Bob Sharp won the GTU class over Brad Frisselle and Jim Cook in a Porsche 911.
Riverside was a cruel setback for Porsche, who couldn't do anything against the BMW works team. Hans Stuck and Dieter Quester won the race over Brian Redman and Sam Posey. Peter Gregg and Hurley Haywood couldn't do better than third in their Porsche Carrera RSR. Bob Sharp and Walt Maas teamed up to win the GTU class in the Bob Sharp Racing Datsun 260Z. Jim Borsos, Dennis Aase and Howard Meister finished second in a Porsche 911.
At Lime Rock, Peter Gregg won the first heat and finished second in the second heat, while Hans Stuck took second and third, Al Holbert wound up third and first. It meant 1-2 for Porsche with BMW third overall with Hans Stuck. Bob Sharp was uncontested in GTU, winning both heats. Tom Ciccone-Bert Everett finished second.
The Mid Ohio race was won by Al Holbert, who beat Sam Posey in a BMW 3.0CSL. Hurley Haywood was next. Bob Sharp again took the GTU class, but Brad Frisselle was threatening his dominance, and was a close second.
Hurley Haywood took the Mosport round, run under 50000 spectators. Carl Shafer was next in his mighty Chevrolet Camaro, with Ludwig Heimrath coming in next. Brad Frisselle took his first GTU win in his Datsun 260Z, Bob Kirby was second in his Porsche 914/6.
The Daytona Paul Revere race fell to Hans Stuck, in his BMW 3.0CSL, who won over Hurley Haywood and Al Holbert. Juan Montalvo took his first GTU win in a Ford Escort, with George Drolsom taking second in his Porsche 911. No hot shot was to be here.
Mid America was all Porsche, with Al Holbert, Peter Gregg and Hurley Haywood taking 1-2-3 in heat one. Al Holbert, Peter Gregg and John O'steen was the finishing order in heat two. Brad Frisselle defeated Bob Sharp in heat one, but was a dnf in heat two, leaving the GTU victory to his main opponent.
Talladega was run under heavy rains but Hans Stuck dominated the race thoroughly. Peter Gregg and Hurley Haywood were next. Brad Frisselle won the GTU class over Bob Speakman and Juan Montalvo, in his Ford Escort.
The Mid Ohio round saw Al Holbert and Elliot Forbes Robinson win the race while John O'steen and Dave Helmick took second. Roberto Quintanilla and Roberto Gonzalez were next in another Porsche Carrera RSR. Bob Sharp and Jim Fitzgerald won the GTU class, with Brad Frisselle-John Morton close behind. They ended up fourth and fifth.
The Daytona Finale was, once again, a preview of what was up to nex season. John Greenwood had his new 1976 car unleashed, and he was virtually unbeatable. Brian Redman and Sam Posey would end up second and third in a horsepower race. Bob Sharp won the GTU class, just ahead of George Drolsom, with Charles Mendez and Dave Cowart in a Porsche 911T.
Peter Gregg was the IMSA Camel GT 1975 Champion.