85% in raw Maths HSC would be a band 6. I know in 2004, 85% aligned to a mark of about 93-94.
65% raw in 4unit would likely be an E4, but I didn't do 4unit, I'm only going off what I've read on here. The 4unit exam is very difficult though, so don't expect it to be easy to get that E4.
In 3unit, something along the lines of 65/84 should net you an E4 (if not slightly lower).
However, remember 2 things:
1) The exams may be easier or harder in a particular year. I did 3unit in 2006 and I think only 58-60/84 was the cutoff for E4 due to the difficulty of it. I doubt I would have beaten 65, and I scored 46/50 in the external exam.
2) If these cutoffs seem low, don't forget that many people overestimate exam performance. The cutoffs I have given are based on the raw marks thread in the Technical Arcana forum. The problem is that many people think that they own an exam, and make many stupid mistakes (the opposite is also true), and you can't gauge how well you'll do in the HSC exam in terms of raw marks based purely on your trial marks.