The Daily Corinthian reports Unique Motorsports, owned by Mike Meeks, was a total loss in a fire that started at about 2:30 p.m.
Meeks said he had just returned from an out-of-town trip when he saw the flames coming from the shop, which was next to Meeks' home on County Road 632.
He said firefighters arrived minutes later.
Meeks said he was able to pull a tractor from a shed and pushed a 1969 Chevrolet Camaro away from the flames, but the loss was severe.
"There's a lot of stuff gone. Probably a million dollars worth of stuff burned," Meeks said. "But there nothing I could do. Just stood back with my hands in my pockets and watched it burn."
Meeks said he lost around $500,000 worth of tools as well as a race car valued at $50,000 and an expensive paint booth.
Firefighters from Kossuth and Union Center were the first on the scene. Officers from the Alcorn Sheriff's Department also responded to the fire.
Cause of the blaze remains under investigation.