a 7T is pretty similar to a nosram 3.5
6T is quite a bit faster
gearing is correct, when the motor reaches a temp of around 80°C
on a large outdoortrack you will find to run gearings down to 6.5-7.5
generally the longer you gear, the faster it gets and the more punch out of the corners it has
indoors you will want to run between 7.8 - 8.5 depending on tracksize