This is one of my favorite web sites. Ive killed hours playing on it. Everything is pretty much spot on. Except the ".Compute ideal MPH and times at 60', 330', 660' and 1000'. They wont match your cars times for some reason. But they are proportionally correct.
The "ET - MPH - HP Calculators" in the first column. And the 'Gears - Tire - RPM Calculators' at the top of the second column are my favorites.
Hope this helps.
Steve-o-
http://www.wallaceracing.com/Calculators.htm