I have two monitors. By default, right monitor has the dash and steering right left monitor shows extension of the dash and the driver's side window.

How can I switch the main FOV from right monitor to left monitor so that the left monitor shows the dash and steering right left monitor?

I guess you added 1 monitor on the left. If that, just put it to zero and add one i the right

Also, at this screen there is also a slider to change where the center of the steering wheel is in the monitor, but I think it can only be adjusted in the range of the main monitor.

Not sure how I added a monitor to the left. My nvidia 210 has a vga and dvi ports and put these two monitors into both ports randomly.

As for the POV centering slider, which screen has it?

LFS->Options->Views