Four-cylinder cars are cheaper and easier to find, Bragunier gave as the reason for the rule change. At least two cars were barred from entering the derby because they did not meet the criteria.
Before the derby began, the eventual winner, Tracy Abbott, was putting a black garbage bag over his front seat to keep it dry. Intermittent rain was falling.
Abbott, 31, of McConnellsburg, Pa., works in a salvage yard and chose a 1991 Chevrolet Celebrity for the derby. His two sons painted it bright orange.
"Just for the fun of it. Just for the adrenaline rush," Abbott gave as his reasons for competing in demolition derbies. "(You) have to be a little crazy."
Richard and Margaret Wolfe of Wolfsville, Md., were sitting in the top row of the bleachers at the Ag Expo more than an hour before the derby was scheduled to begin.
They participate in derbies regularly, but were spectators this year, in part because an unexpected problem with their well strained their finances.
Their passion for smashing into other cars wasn't so easily quashed.
"We don't drink. We don't do drugs. We race," Margaret Wolfe said.
"I love it," Richard Wolfe said. "You just got to be smart and use your car to your advantage."
Trying to knock out another car's axles while avoiding head-on hits that could bust one's own radiator are among the tricks to winning a derby, they said.
Like other sports, of course, there are other not-so-talked-about tricks. Richard Wolfe said he probably would wander over to the cars before the derby.
"See what they're cheating on, and who's cheating and who's not," he said.
Secretly filling car frames with rebar or concrete to make them stronger can be done, he said.
One underhanded way to try to win isn't allowed. "Playing possum" - or purposely avoiding hitting other cars for 30 seconds or more - will result in disqualification, Bragunier said.
Nobody was disqualified for that reason Friday because all six drivers continually smashed into each other until car after car quit running. Within minutes, the muddy field had claimed a few bumpers. One car had its rear end momentarily stuck on a concrete barrier.
Most of the crashes prompted "oohs" from the crowd, but a few of the harder ones garnered expletives.
Some in the derby audience were novices.
Russell Hose and his wife, Debby, were attending their first Ag Expo demolition derby.
"I know it's going to be a lot of crashing," Russell Hose said beforehand. "A lot of banging. A lot of excitement."
Walter Martin, 15, said he has attended a couple of demolition derbies.
"It's a lot of action, that's for sure," he said.
Martin didn't immediately rule out the idea that he might one day get behind the wheel of a junk car, pull on a helmet and strap himself in for a bumpy ride.
"It would be pretty fun, I imagine," he said. "Probably better than racing."