Martin sets wins in a season for a #5 car:

Mark Martin made 2009 the most successful season ever [in term of wins] for the #5 car in terms of wins, Martin won five races in 2009, the most ever by the #5 car. The car #5 has won a total of 39 races in 1277 starts. Below are the top four seasons for wins by the #5 car.
Year, Driver, Wins
2009, Mark Martin, 5
1995, Terry Labonte, 3
1994, Terry Labonte, 3
1984, Geoff Bodine. 3
Most Wins in car #5: Terry Labonte with 12
BUT Terry Labonte won the 1996 Sprint Cup Championship running the #5 car, winning 2 races.(ESPN and Racing Reference)(11-27-2009)