DALE EARNHARDT JR. spent as many as six hours a day in the off-season preparing for Sunday's Daytona 500. Not on the track, but on iRacing.com, an Internet simulator launched last June. Four years ago Junior was asked by John Henry, the Red Sox' owner who also co-owns iRacing, to help develop the game. Using a high-tech laser scanner, most tracks on the Sprint Cup schedule were replicated in spectacular detail, and Earnhardt has spent about 200 hours perfecting a virtual car, which he has been tooling around the faux Daytona International Speedway from the comfort of his home for the last few months. "It helps me just as much as a test session at an actual track," Earnhardt says. "You learn judgment calls, what lines to use, what decisions you need to make in the draft. I guarantee on Sunday this is going to give me an edge."