McCombs was a member of the Alamo Endowment Board, which raises funds for the preservation and management of the Alamo Mission in downtown San Antonio. With the state purchasing three historic buildings in Alamo Plaza, McCombs said in October 2015 that he envisioned an expansion program consistent with the reality of the Alamo story to enhance the overall experience of future visitors to the historic site. In 2017, McCombs filed a $1 million civil suit against seven of his former executives who he alleged took "trade secrets" from McCombs' company to begin a competing firm in Houston, F4 Resources. Defendants in the suit include William "Bill" Forney, Jr., who worked with McCombs for forty-four years, former chief financial officer Ricky Halkin, vice president of operations Larry Wyont, vice president of land Charles Forney, and the vice president of geology, Philip Forney. McCombs had established McCombs Energy in Houston in 1998 by merging his 50 percent interest in his partnership with William Forney with other assets purchased from Forney. McCombs claimed that his former associates, however, lowered the proper payout that he was due from his investments. McCombs said that the former executives shattered personal relationships of some four decades. Sports ownership McCombs attributed the construction of the HemisFair Arena as the essential development to the success of the San Antonio Spurs. He contacted Lee Iacocca, then president of the Ford Motor Company, to seek funding for the arena to correspond with the 1968 World's Fair. At first, Iacocca offered only $250,000 for the purchase of an art object, and he scolded McCombs and ridiculed San Antonio as "that little old dusty ass town of yours down there [with] no political or economic significance to the Ford Motor Company." McCombs persisted and asked U.S. President Lyndon B. Johnson to contact Henry Ford, II, and in a continued heated exchange even told Iacocca that Ford needed to improve the quality of its 1968 vehicles. McCombs located other investors, and the Dallas Chaparrals came to San Antonio five years later in 1973. McCombs realized the importance of television to sports events and saw the opportunity to bring San Antonio to a national stage. Under the McCombs administration, the Spurs had their first superstar in George Gervin, called "The Iceman", who was recruited from the Virginia Squires. Two years after taking the Spurs into the NBA, McCombs sold off his stake in the Spurs