This article relies largely or entirely on a single source. (July 2016)
December 9, 1935
Las Vegas, Nevada
|Awards||1970 NASCAR Grand National Series Rookie of the Year|
|Monster Energy NASCAR Cup Series career|
|83 races run over 12 years|
|Best finish||18th (1971)|
|First race||1962 Capital City 300 (Richmond)|
|Last race||1981 World 600 (Charlotte)|
Dennis made his debut at age 26 at the 1962 Capital City 300 in the No. 98 and finished 15th. After three part-time seasons, he attempted a full-time schedule in 1970 and he had five Top 10 finishes for Donlavey Racing. He was given the NASCAR Rookie of the Year award in 1970. He competed full-time for the last time during the following season for Donlavey and had ten Top 10 finishes and a pole position. In 1972 he competed for three teams and earned two Top 5 finishes. He competed in a few races until his last start came in the 1981 World 600.
Dennis won the Permatex 300 at Daytona three consecutive years (1972–1974), a feat matched only by Dale Earnhardt and Dale Earnhardt, Jr, and later surpassed by Tony Stewart, who won four consecutive from 2008-2011.