The spray nozzle is located in the slotted cowl between the windshield and the hood.
Sometimes the windshield washer pump on my 82 FSB, which is located in the windshield washer reservoir, will quit working. I have had to remove the pump from the reservoir and manually turn the impeller to free it up. It will work correctly after that. This usually happens after a very long time of not using the pump.
I'm assuming that since you don't know where it is that it's completely missing. Mine was missing when I got mine (it's an '81 as well). In the middle of the vent cowel in front of the windshield (more on the drivers side) there'll be a hole about the size of a dime. That's where the squirter goes. I think you can get them from Ford for pretty cheap.