100 pound loss = how much HP gain???

I think another interesting question is shifting location of the weight.
That clearly wouldn't relate to the maximum hp unless it was on the rotating mass - then it might.
I think David Vizard had some tests in Popular Hot Rodding where it showed no measurable power gains by taking weight off the driveshaft, but measurable gains when other components were lightened. My friend had the issue - I remember unsuccessfully looking for it in the stores but was sold out.

With respect to ET, I'm sure on some cars removing weight in the nose or front wheels vs over the axle would have different effects on the 60'.