This, and his performances in his self-funded Commodore in the 1983 ATCC, brought him to the attention of Peter Brock and the Holden Dealer Team, and with the help of Janson he was drafted into the HDT for the 1984 Australian Endurance Championship.

Parsons co-drove with John Harvey to a DNF in the Oran Park 250 in Brock's ATCC car, before the pair went on to finish 3rd in the 1984 Castrol 500 at Sandown in the second of the team's new VK Commodore's.

Late in the James Hardie 1000, Parsons was "let off the leash" by team owner Brock who told him to go for second place which was held at the time by 1980 Formula One World Champion Alan Jones who was driving Warren Cullen's similar VK Commodore.

Parsons was retained as a driver for the HDT into 1985, although results were harder to come by as the Commodore initially struggled with engine unreliability in Australia's move to the FIA's Group A rules.

Inspired driving on variable surface as rain plagued the second half of the race, good strategy and a lucky break with safety car procedure saw the team claw their way past the BMW M3s as they failed, and the Nissan Skyline turbos and into third position behind the flawless 1-2 finish of the Eggenberger Motorsport Ford Sierra RS500s.

[5] Parsons stayed with the team into 1988 as they transitioned from V8 Holden Commodore's to 4 cyl BMW M3s, although by now in Australia the giant killers of 1987 had become little more than class runners in the face of the all-powerful Sierras.

The highlight of his time with GSR was winning the 1993 Sandown 500 co-driving a Ford Falcon (EB) with Geoff Brabham and qualifying in the top ten at the 1991 Tooheys 1000 in a Sierra.