how do i figure out trap rpm with my diff gear?

crackedback said
All sorts of calculators here:

http://www.wallaceracing.com/Calculators.htm

using the mph-gear ratio calculator i ended up with needing a 29 inch tire and 4.56 gears with the final tranny ratio being 1:1 in order to pass the traps at 6000rpm going a speed of 113mph...that sounds faster than a high 12/low 13 second car