Around 40 members of the Bay of Plenty Vintage Car Club were present for the unveiling. Mr Allen has been a member for 48 years.
"Once upon a time I was the youngest member but now I'm getting to be one of the older members. There's still older than me though."
The Alldays & Onions was wrecked in the 1930s in the South Island Waimate area. The vehicle's chassis, bonnet, radiator and engine then passed through several hands, and areas, including Oamaru and Wellington, before being reunited over half a century later.
The 70-year-old, who has been restoring cars for 50 years, received the car in 1997 but was working on other vehicles at the time.
"I thought I better get going with it because I would be too old to do it soon."
Mr Allen's other classic cars include a 1.6 litre single cylinder 1907 Cadillac, a 1911 Wolseley, which took 6000 hours to restore, a 1913 Renault, a six cylinder 1929 Austin Sedan, a six cylinder 16 HP 1929 Austin Tourer, a 1934 Austin 18 and a 1947 Austin 16.
Upholstery is the only part of a restoration Mr Allen does not undertake. The former owner of a spray painting business is entirely self-taught.
"I enjoy doing things with my hands. Every day you've got to have something to do."
And he will have plenty to do as he sets to work on the 1929 Austin Tourer which he predicted would take up to four years to finish.
The cars were a labour of love and not necessarily a pleasure to drive.
"Noisy, uncomfortable, and they've usually got poor brakes, so it's best if you keep away from other cars," he said.
Driving the Alldays & Onions, was "like trying to tame a wild, racehorse".