Ace found the amazing in game FOV adjustor for one of the apps.
Go here....
C:\Program Files (x86)\Steam\SteamApps\common\assettocorsa\system\cfg
Open assetto_corsa.ini file using Notepad
and set
ENABLE_DEV_APPS=1
now when in game and driving.. stop the car.. bring your mouse curser to the right of your screen and you will now see a whole bunch of icons.. look for the one that says, on board setting..