The water drain locations on every late A body (67-76) that I have seen are in the sides of the cowl. Open the doors and look at the sides of the upper cowl and you can see them. There are at least one on each side. The best way to clean them out is to remove the drivers side air vent box so you can reach up into that side and pull the leaves and crap out by hand. When you get as much out as you can get a hold of, use a shop vac with some type of smaller modified hose taped to the regular hose to vacuum it out. If you aren't afraid to tackle it, take the heater box out and do the same on that side. You can also use an air hose with a blow nozzle on it to herd the debris to where it is easier to get out. Use a small mirror and a drop light or flashlight to look into the cowl. If you're high tech, use a small bore scope that hooks to your cell phone. That's all I've got, so good luck!
