if this is all new to you, then I would discourage you to run a SV.
I mean, the SV is an all out competition car. Not the best car if your starting out.
FDR stands for Final Drive Ratio, which is the final gearing of the car, which is calculated by, which in this case is:
spur (81 or 83?)
divided by
pinion (your choice)
multiply by the cars internal ratio (2.6)
with a 10.5, maybe an fdr of 8
so go for around 24 or 25 pinion to start off