Well you're right, there is no skill involved with racing from 80mph.
You can't really quantify how quick a car is 80-115. I've only been to the track once, and ran 7.98 at 88 in the 1/8 on my fourth pass ever. On that day it was the quickest of nine n/a 5.0s at the track and nearly all of them had tunes and exhaust. It was also quicker than the two supercharged 3-valve GTs there. I think I can back up my claim. What have you run?
I've run quick times in other cars and bikes that I've owned but haven't been to the track with my auto yet.
If your stock from what your telling me, it's not your car that is more powerful/better geared than tuned auto 5.0's or other, it's that you know how to drive...
A roll race can give a good idea of power to weight taking out a lot of the skill part of the launch.