"It involves testosterone, adrenaline and petrol ... What more could you want?" Brian Kyles, of Oamaru, said at the Otago Land Rover Owners' Club annual "Mud Plug" at Waitati yesterday.
Mr Kyles (55) and his son Brian (28) built and modified their mud-brown Toyota powered by a 6.2 litre, fuel-injected Chevrolet V8.
"We've been modifying the truck for years. We bring it out here, break it, take it back and fix it and then bring it out again," Mr Kyles sen said.
The vehicles had to negotiate 11 mud hazards and one speed trial in the "Mud Plug".
"The object is to get through the course with the minimum penalties," Mr Kyles sen said.
"You look at the land and look for a spot you can pick a path through that suits your ability and your vehicle. There's no perfect vehicle. They're all good at different things."
But there was always a price to pay for fun, he added.
"I'm not allowed in the house when I get home. My wife, Heather, makes me get undressed at the back door and then I've got to throw my clothes on the lawn and hose them down."
Otago Land Rover Owners' Club committee member Stu Robie said 18 vehicles from North Otago to Bluff took part in the trial.