Untouched for 50 years, the totally original Italian machine is one of just a handful left in the world from an original production run of 600, and was the first production vehicle ever to use a straight-eight engine.
Despite its derelict condition, the Tipo 8 was purchased by Melbourne restorer Glenn Olsen, whose firm Olsen's Classics will undertake a complete restoration. The car is expected to be worth in excess of a million dollars when the restoration is completed. Last year, a restored 1924 model Tipo 8 phaeton sold at auction for US$447,000.
"Motorclassica is delighted to be able to feature whats probably the most significant 'barn find' anywhere in the world this year," Motorclassica Event Director Paul Mathers says.
"It's a hidden treasure ... and it was right here in Melbourne and no-one knew, it's an amazing story and what an exciting car."
Olsen plans to display the car annually at Motorclassica throughout its restoration.
"It took eight people most of the day to extract the Isotta from its cave, along with the body tub, doors and guards that were hidden in the loft above," Glenn Olsen explains.
In its fourth year, Motorclassica 2013 will see more than 150 cars on show inside Melbourne's Royal Exhibition Building, with another 200 cars outside in club displays each day.
This year will see the event mark special anniversary milestones for Lamborghini (50 Years), Chevrolet Corvette (60 Years), Aston Martin (100 Years), Bertone (100 Years) and Harley-Davidson (110 Years).