Under the patronage of Porsche Cars Australia distributor Alan Hamilton,[2] Costanzo won four Australian Drivers' Championships, the CAMS Gold Star.
Costanzo commenced his Formula 5000 career racing a Lola T332 which he purchased in partnership with his brother in law and team mechanic, Marino Ciuffetelli.
Alf led from the start of the 1983 Australian Grand Prix, and built up a small lead over eventual winner Roberto Moreno of Brazil, before the diff in his Tiga FA81 failed on lap 25.
Although formula cars have evolved and have generally gotten faster over time, Costanzo still holds an outright lap record for a still active Australian race circuit.
While a more than capable touring car driver, finishing fourth in the 1979 Hardie-Ferodo 1000 alongside Allan Grice he was generally overlooked for drives by the top teams and was never able to establish himself full-time in the category, and the popular Italian-Australian faded from the racing scene when he left Formula Pacific in at the end of the 1984 after finishing 4th in the Australian Grand Prix held at Melbourne's Calder Park Raceway.
At the insistence of his long-time open wheel rival turned touring car racer John Bowe, who to this day rates him as the best Australian driver he raced against, Costanzo was drafted into the Volvo Dealer Team in 1986 for the Castrol 500 at Sandown and the James Hardie 1000 at Bathurst.
Again at Bowe's insistence, Alfie was the drafted into the Dick Johnson Racing Team for Sandown and Bathurst in 1988 to drive a Ford Sierra RS500.
Prior to Sandown, Romano wanted Costanzo as his co-driver for the race, but both Wayne Eckersley and team manager Bruce Ayers tried to persuade him to go with either the 1984 Australian Drivers' Champion John Bowe or 1983 Sports Car champion Peter Hopwood for the event, reasoning that both would be easier on the car than Costanzo who although fast, had a reputation for being hard on equipment.
Grant Nicolas, Alfredo Costanzo – The Italian Australian Open Wheeler Champion, Motor Sport Legends, Aug/Oct 2008, pages 20–26