I reckon David! is right on this point. Having been a consultant at Ford Australia I know how hard the cars are tested. Please let's not confuse crumple zones, lots of plastic and the like with weakness. The crash tests now in force would see no cars from the 1950s or 1960s passing. Somewhere there's a video of (I think) a 1959 Chevy doping a barrier test and failing catastrophically. One real negative on the Phillip Island circuit the way it broke up in those first three years and particular 1962 would be 40-series rubber! They had small wheels, the cars of that time with 80-Series or taller rubber. But if the regs permitted 60-series tyres, then, I believe, no worries for the kinds of cars wise entranrts would choose.