Complex sentence: He remains the only driver to run more than six races for a team owned or co-owned by Reeder; at the end of the season Martin sold off the team, having signed with Jim Stacy to race in 1983.
Split into simpler sentences: He remains the only driver to run more than six races for a team owned or co-owned by Reeder. At the end of the season Martin sold off the team, having signed with Jim Stacy to race in 1983.