After the 1974 season, citing a lack of interest to run the facility as a collective group anymore, New London-Waterford Speedbowl, Inc. put the Speedbowl property on the open market. Developer Michael Carrado had an exclusive window to purchase the property, but ultimately did not do so and the Speedbowl went back on the market in January 1975. Less than two months later, it was sold Harvey Tattersall Jr, president of the United Stock Car Racing Club and long-time promoter of Riverside Park Speedway in Agawam, MA – the only other remaining track on the once-prominent United circuit. This marked the end of a 24-year run for the original owners, the longest tenure of any operating group in track history.
Also serving as Race Director, Tattersall immediately implemented the United sanctioning rules in both Saturday divisions. In the Modifieds, cars with 340 cu.in. and up would compete for the Modified title only, while the smaller powered Sportsman machines, that also ran in the division, would compete for the Sportsman title separately. Both a Modified and Sportsman point champion would be crowned at season's end. This system lasted until 1977. To keep consistent with United rules, Tattersall also renamed the the Sportsmen Sedan division as the Grand American Late Models. The season-opening event would be called Blast Off! and was promoted as the kick-off the racing season in the northeast. Also implemented was the Grand Slam Series – a series of extra distance events to end the season. The driver with the best overall finish among the events would also be crowned the Overall Grand Slam Champion.
In the Modified ranks, it was once again Dick Dunn winning the points title – extending his record consecutive track championship streak to 4. Dunn won 5 races during the year, including the Mid-season 100, then the Fall Stinger 100 and Grand Slam 100 in consecutive events to close out the season. Bob Potter led the Modifieds in wins with 6. Potter won a 100 lapper in June and the Grand Slam 50, as well as earning Overall Grand Slam Champion honors. The last 10 races of the season were won by either Potter or Dunn. The legendary "Steady" Eddie Flemke won the season opening Blast Off 100 in John Stygar's #7 Pinto and Billy Harman won the Memorial Day Weekend 100. The first Sportsman Modified champion under the United banner was Mark Lajeunesse.
The Yankee All-Star League debuted as part of a 6-race, tri-track point series with Thompson (CT) International Speedway and Star (NH) Speedway. The very first Yankee All-Star race was held at the Speedbowl on July 16th with 20 year old Ken Bouchard taking the 50 lap victory over Richie Evans. Ken's older brother Ron Bouchard would win the second Speedbowl event in August. After the 6 race series was complete, Ken Bouchard was crowned the 1975 Yankee All Star League Champion. For more information on this unique series click here.
Roger Charbonneau won a division leading 5 feature events including a double point 50 lapper on the finale weekend, but he still fell a single point shy of 4-time winner Donny Fowler in the final point standings. Fowler lost a wheel during the Finale and had a DNF, but with only 10 cars left on the track at the time, he finished 11th – just enough to claim the title despite Charbonneau's victory. Earlier in the season, Rick Elnicki won the 50 lapper during Memorial Day Weekend and Mike Daignault won the 40 lap event during the 4th of July weekend event.
The Speedbowl added a special midget program to the July 5th event. Johnny Evans won the 25 lap NEMA midget feature and Johnny Holmquist won the ATQMA 3/4 midget 25-lapper. There were also 3 Volkswagen events were held during the season. Jack Kane won the two 15 lap events while Tom LaPointe was declared winner of the 10 lap event in July after Roger Boissonneault was DQ'ed.