A company called Smithy's located at Bayswater. They were recommended to me by one of the Holden dealers. I called Smithy's and they said that they would send me some information about LPG conversion, which they did. I was surprised as I didn't expect to see anything in the mail. Hopefully this level of professionalism carries on to their workmanship as well.
Anyway, its a genuine IMPCO duel fuel system with 4 valve LPG cylinder (94litre=74 litre usable capacity). Uses your petrol gauge to display the LPG level. Quality brass water fittings and hoses, electronic modules located under dash board, wiring made with solder, 3 year/100,000 KM national warranty, vehicle dyno tuned and complementary return service and adjustments.
Contact details: 9762 2333 (Smithy's car repairs and lpg conversions)