Harper has now owned the car for 35 years and uses it often. He said it would have been at the top of the range when it was first built. It was restored in 1972.
He said it was reasonably difficult to find parts but he tried to keep it as original as possible.
"They [Studebaker] were quite innovative in their engineering and styling. When they came out they would have looked like they were from Mars."
Harper's was one of about 40 Studebaker cars on display at the 25th nationals.
One of the organisers, Andre Haan, said more than 10 of the cars had driven from the South Island to be there.
Most of the drivers belong to the Studebaker Drivers' Club, he said.
There are 14 categories the vehicles will be judged in, plus an overall winner.
The vehicles are judged on interior, exterior, engine bay and boot, said de Haan.
He said the comraderie is what made the event special.
"We all get together and become a big family. When you're in Studebaker you pick each others brains when fixing them up and swap spare parts," he said.
"We've been in the club for 15 years and i just about know every car owner by name."
The Studebaker Drivers Club of New Zealand is celebrating its 50th anniversary and its 25th national event. Its headquarters are in Christchurch, but its 220 members are spread across six regions.
Each year the national meet is held at Easter.
Studebaker originally built horse-drawn buggies, carriages and wagons, which were a primary mode of transport as North Americans migrated westward and were used by several US presidents.