By Dave Caldwell More than three months after he said he would drive a racecar for Hendrick Motorsports in 2008, Dale Earnhardt Jr. announced yesterday that his car would carry No. 88 and would be sponsored by Amp Energy Drink and the National Guard. “I never thought a car number would create as much excitement as it did in this situation,” said Rick Hendrick, Earnhardt’s future boss. Earnhardt’s announcement, made at a news conference at the Dallas Convention Center and carried live by the Speed Network, was probably the most eagerly awaited moment of the Nextel Cup season. Almost anything Earnhardt plugs tends to sell. Earnhardt, whose current No. 8 car is sponsored by Budweiser, remains the series’s most popular and marketable driver, even though he did not qualify for the Chase for the Nextel Cup this year, his last with Dale Earnhardt Inc., a company started by his father, the seven-time series champion Dale Earnhardt Sr. “The whole retail industry was literally waiting down to the minute to the point when his new car became available,” Mark Dyer, the president and chief executive of Motorsports Authentics, a Nascar-licensed merchandiser, said in a telephone interview. “I think he’s in the absolute top echelon of American sports celebrities. Certainly, it helps that he’s the son of a real American icon, but he stands on his own as a sports identity.” Hendrick Motorsports announced July 13 that Anheuser-Busch, which makes Budweiser, would not continue to sponsor Earnhardt’s car. On Aug. 15, Hendrick said Earnhardt would not continue to drive the No. 8 car. PepsiCo, which manufactures Amp Energy Drink, has been a sponsor of Hendrick’s cars for 12 years. Earnhardt’s cars will also carry the logo of Mountain Dew, a PepsiCo product that has been a Nascar sponsor for almost 50 years. Lt. Gen. Clyde Vaughn, the director of the National Guard, said that sponsoring Earnhardt’s car made business sense, because stock-car racing has a wide appeal to National Guard members — and American men and women who may sign up. The pursuit of a number for Earnhardt became the subject of great intrigue. Earnhardt wanted to continue driving the No. 8 car, but Teresa Earnhardt, Dale Sr.’s widow, did not want to part with the number. He looked for a number with an 8 in it. Hendrick got No. 88 from Robert Yates Racing. Kelly Earnhardt, Dale Jr.’s sister, first inquired about No. 28, which Yates was not using. Instead, Yates transferred No. 88, a number used by Earnhardt’s grandfather Ralph to Hendrick. “Ralph Earnhardt drove the No. 88 Olds in 1957, and because of this number’s history with the Earnhardt family, I felt car No. 88 should continue with Dale Earnhardt Jr.,” Robert Yates said in a statement. Drivers in the No. 88 car have won 65 races at Nascar’s top level, compared with 38 for the No. 8. Included in a long list of No. 88 drivers are such stars as Ricky Rudd, Bobby Allison, Dale Jarrett, Benny Parsons, Fireball Roberts and Darrell Waltrip. “I like the fact that the number has some history,” Earnhardt said. The No. 8 car will be sponsored by the United States Army next year and will be driven by Mark Martin and Aric Almirola.