One-half of the NASCAR Cup Series season left until Martin Truex Jr. officially hangs up his gloves and helmet for full-time racing. The keyword here is “full-time.” It has become more common for retired drivers to keep driving part-time recently. At least, it feels that way. I’m sure there has been precedent before. But it appears that Martin Truex Jr. could take the Aric Almirola route in retirement. When asked about a potential Daytona 500 start in the future, a race that has eluded Truex in his career, the driver left the door open. “Maybe. I don’t know, I’d be open to it,” Truex said. “[J…