Calculating your speed in gears is not too difficult you just need a couple of pieces of information and a handy calculator like the one in the link below.
Before clicking on the link below, you’ll need to know:
your tire size if you need help with this ( click here )
Your rear axle ratio
your gear ratio in the transmission you’ll be using
Simply click on the link below to calculate your Speed in different Gears
TREMEC CALCULATOR LINK