I'll be able to confirm all the specifics next week as im taking a break for a week off work, and getting back in touch with the engineer when i get back. Spoke today briefly to him and VicRoads have implimented another rule that goes by vehicle weight to measure max cubic inches. Power becomes irrelavant now, which has always been a sticking point for engineers.
eg- previously laws satated that the max cubes for a HQ was 400ci.....new rule formula says 427 is possible. One engineer i spoke to said he could pass 454ci if i did a bunch of chassis and suspension mods. this rang alarm bells for me because if i went for a 396ci BBC, because off the smaller cubes, i wouldnt need chassis and suspenion mods,....but the engine weight would be virtually the same. There are way too many grey areas between engineers.....but until i can get the law in black and white, i dont believe what i hear or see.