In the 75-76 cars, the flapper valves hook directly to the injectors.
Pics of a 73-74 2.0 setup:
S-duct that runs from the fan shroud to the heat exchanger--
J-tube that goes from above the engine tin to the side of the S-duct--
The two of them hooked together--
The flapper valve and the pipe that goes from the valve to the heat exchanger--
The J-tube, S-duct, flapper valve and pipe, and the heat exchanger--
A view of the whole setup for one side--
Another view--
--DD