nixie tube speedometer

[Add_man]

So ok, I have this somewhat unusual idea of adding an auxiliary nixie tube speedometer display to my car.( i would keep the old one in place.)

 I was thinking of using the small in-17 tubes and powering the HV board off the 12v car supply. while controlling them using a simple microcontroller. and would used a pass through speed sensor to capture the speed data.
but... my car gas tanks right next to the dash (like within a foot of each other and within the same compartment) and I'm worried about 10.5 gals of gasoline sitting, sloshing and venting next to 170v (although it is low amps).  Do you'all know if this would pose a risk? or would this be a fireball death trap?