I have noticed the 80's range is pretty competitive. Don't let these 90 PCAT takers on SDN fool you. Not everyone is THAT smart b/c with a 90 score, there has got to be a 60 score =)
I was thinking more on the lines of a 3.9 GPA applicant will still be competitive with a 70 PCAT. Whereas a 3.4 GPA applicant would need to score in the upper 80's to 90's on the PCAT to be competitive.