Well I guess it depends on how you define redline.
7200 rpm is when the valve float really kicks in and the engine just won't spin any faster. I've only done this once or twice, just to see where it was. Not something I'm in the habit of doing.
But the 6300-6500rpm range seems to be right where the torque curve starts to drop off. She still pulls real hard from 6k to 6300-6500 or so. I have my shift light set at 6200 so I am sure to shift before 6500
Again I'll reiterate how rarely I do this to my engine (I sure as hell don't want to pay to fix anything), but I've done it enough to know that these numbers are correct (that is, of course, assuming my tachometer isn't off). I really only do it if and when I go to the strip (which I haven't done in many years). Best ET was 13.61