It depends on which event you wish to run. Targa Tas, Targa Wrest point, Mt Buller, Lake Mt Sprint ran under AASA regs. Not sure if they default back to the CAMS regs or not. I know there are differences in the modern section between CAMS and AASA regs.
Classic Adelaide and Suncoast (if it runs again) are under CAMS regs.....
On the website there are the regs for both modern and classic tarmac rally cars.
http://www.camsmanual.com.au/pdf/04_rally_road/RR05_Tarmac_Rally_TechRegs-Classic_Q309.pdf