Austrailia eh? I think that is the best place to race a car...really fast over there. If you raced at LACR(Los Angeles County Raceway) i bet your time would be almost a full second slower. Its typical of all times in the magazines...a bmw m3 runs a 13.5 in the magazine, but at the track they run mid to high 14s.
I bet your car is pretty damn fast though with the big block in there...have you done a chassis dyno? Engine dyno? Raced it in the quarter mile? With Slicks on?
You are probably most definitely in the top 5.