The 6 hour relay is an endurance event at Eastern Creek, held around October each year.
The idea is that a team of min 3, max 6 cars competes in a "relay" type event, where one car is out on the track at any one time. After practise, each driver nominates a time to which they think they can stick. Handicaps are awarded to each team, based on each drivers nominated time. If the handicap works out ideally, then each team will have completed the same number of laps at the end of the six hours.
If any driver goes quicker than their nominated time, that individual lap doesnt count toward the total number of laps your team does. The winner is the team that completes the highest number of laps in the 6 hour time.
Then of course there is line honours - for the most number of laps outright.....
www.alfaclubnsw.org.au has more info
The race is open to log booked cars as I understand, so roll cages etc are required. This will probably limit the number eligible cars....
The mini club of nsw has won it a number of times, but werent competing last year.