A part of the group that owns baseball's Boston Red Sox is close to buying as much as 50 percent of Roush Racing, the founder of the Nascar stock-car team said. Jack Roush said an agreement with Fenway Sports Group to shore up the team's finances as Toyota Motor Corp. enters the biggest North American racing series might be finished by the end of March. Roush, whose teams won back-to-back Nascar championships in 2003 and 2004, said Fenway would take a 25 percent to 50 percent stake in Charlotte, North Carolina-based Roush Racing. He declined at a Charlotte news conferenceto give financial details., which has been in negotiations since September.