Dale Earnhardt Jr. off to best start of his career AP 3/18/2013 3:52:22 PM (AP) Dale Earnhardt Jr. off to best start of his careerBy JENNA FRYERAP Auto Racing WriterBRISTOL, Tenn.Dale Earnhardt Jr. has quietly put together the best start of his NASCAR career.Earnhardt has opened the season with four top-10 finishes for the first time in his 14 full years in the Sprint Cup Series. He's done it with little flash and by grinding away as he did Sunday with a late charge at Bristol Motor Speedway to a finish sixth.Earnhardt rallied from a poor qualifying effort _ he started 32nd _ and credited crew chief Steve Letarte for making the right adjustments on the No. 88 Chevrolet."He made a couple, two, three great pit calls there at the end, and gave us the opportunity to get some guys on some old tires, and beat a few guys that we probably weren't going to beat. Great call by him," Earnhardt said.One call was a two-tire stop that moved Earnhardt to 13th on a restart, giving him critical track position late in the race."The track was really tightening up fast and caught us off guard and we weren't really ready for it but we made some great changes at the end and Steve had some great strategy on the tires and we were able to salvage a good finish," Earnhardt said. "We got the car running better and I have to give the car a lot of credit, but Steve deserves the most credit because the strategy that he ran there in the last 150 laps really got us our track position."But Earnhardt wasn't satisfied Sunday, even though he heads to California this weekend ranked second in the standings. He believes his Hendrick Motorsports team has a lot of room for improvement, and he may be right: Although Earnhardt has finishes this season of second, fifth, seventh and sixth, his 47 laps led at Phoenix is the only time he's been out front so far this year."We had a lot of attrition (at Bristol) as a lot of guys wrecked out and that certainly makes your day easier when you aren't racing the whole field out there," he said. "So we have to do a little bit better and I am not real satisfied with the overall performance. But what Steve does on pit road is magic every week. He is pretty sharp."