The No.33 Kevin Harvick Inc. Chevrolet driver crossed the finish line 4.21 seconds before Erik Darnell.
The win was Hornaday's fourth of the season and 33rd of his truck career.
Rain canceled qualifying, but points leader Hornaday brought the field to the green flag.
Behind him were his primary championship rival, Mike Skinner (-4), 2006 series champion Todd Bodine and Mike Bliss.
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