We do not have the complete story of 1973. It was certainly "the wet one", so there would have been lots of stories.
This observation was written by Ross Dunkerton for the 2002 Reunion:
1973 was my first attack at the Southern Cross. The event was run in horrific weather conditions and many roads became impassable. My most vivid memory of that year was tackling a very steep hill at night in my standard 180B SSS. Cars were bogged all over the hill. With pedal to the floor, I managed to pass all but one of them, a Mitsubishi Galant. The car behind me decided to have one more try and edged a bumper in front of us. As it was obvious none of us were going anywhere, all three drivers decided to negotiate our way out with each other, and we agreed to assist each other over the crest. We would push the first car, then all push the second and so on. With much grunting and groaning the six crew members from the three front cars pushed the Galant over the crest, but once freed they disappeared into the night! With only four people left to push the remaining two cars, we managed to get the Mazda over the crest. This time the competitor returned as agreed, but our Datsun was too firmly stuck for just the four of us, who by now were exhausted.
Eventually we did get out by going back down the hill but it was a continuous grind to the finish. In fact, I remember one stage was so slippery my car started to slide backwards off a cliff, when the handbrake wouldn't hold it. I had to jump out and lay under the back wheel to stop it sliding into the ravine. Such are the recollections of my first Southern Cross and what I took away from it was, never rely on another competitor to get you to the end, and no matter how bad you think the weather is, it can always get worse.