Hey Rudy,
Sorry it has been so long since I have had a chance to comment here. With an 18-month old girl in charge around here my time is rather limited.
In regards to the ratio of 6.8, it is the rear end ratio that was in the bus when it left the factory.
In regards to the engine being an 1160, it is the older version of the 3208 and some think it is a better engine than the 3208. I know most people believe the fuel injection pump is better.
The piece you identify as the governor is in actual fact the injection pump that includes the governor inside of it.
I am not sure exactly to what you are referring in the picture with the screw in pipe fitting in the intake. I can't tell by the picture what sort of line is going into the fitting (fuel?, air pressure?, oil?). Without knowing what the line supplies or is supplying I have no guess.
In regards to keeping the interior warm during cold weather, you have two choices--you have to either keep the heat in or have a larger source of heat. Or a combination of both. Either way, blocking off windows during the winter and blocking off unused spaces would be a good first step.