I think this year used a cable operated vent control. They also had a vacuum controlled valve to shut off the hot water to the heater.
http://www.ebay.com/itm/162751931620/www.ebay.com/
http://www.ebay.com/itm/172463480850/www.ebay.com/
This was the type on my 1979 Impala. The parts store sells vacuum hose which you can cut 1 11/2 inch piece and push on any broken plastic lines.