I too have a 1970 1600 GT crossflow. I had similar problems starting the car after it had stood for a while.. This was due to lack of fuel in the carb ,(proved by squirting some gas directly into the carb after which the car started at once - ie there was nothing wrong with the spark). This lack of fuel is either due to evaporation or more likely to the fuel running back from the mechanical pump because the pump's internal valves are sticking open or not closing - probably worn . Being a mechanical pump it needs quite a few revolutions to suck up the gas, if it has run back towards the tank. My problem was cured by putting a new mechanical pump on .....Good Luck....Terry
