I'm in Victoria and help other Vette owners with their cars. I only work on the C3's. I picked up an 80 Vette a couple of years ago and have been slowly getting it ship shape in my spare time, LOL It seems that the heater cores in the cars in the 80's are susceptible to failing as I know of an 81 that currently has the same problem. All of the 80's had standard air conditioning and the heater core has to be removed from inside the vehicle. The problem with the missing vacuum line is also common as a lot of previous owners removed the smog equipment that was on the cars and inadvertently affected the timing and other systems. I would be happy to have a look at your car if you get a chance to bring it to Victoria.