First thing - make sure you're editing the 'SnapViews.lua' and not 'SnapViewsDefault.lua'
Then find this bit of code.....
[13] = {--default view
viewAngle = 83.847038,--FOV
hAngle = 0.000000,
vAngle = -12.471437,
x_trans = 0.358480,
y_trans = -0.041337,
z_trans = 0.000084,
rollAngle = 0.000000,
....and set the 'viewangle' (FOV) to what you want.
One thing to note - when you first enter the cockpit the FOV will not be e.g 83.8xxxx so you need to hit 'reset zoom' using Keypad_Enter.