From what I read most people have this problem on the passenger side, but on my 85' Brat it is on the driver's side. 

 

The only thing I have messed with is the hood cowling, and that was to work on a fender. Could that have done anything? The leak Is pretty is bad. It is most definitely rain water, as I'm not loosing coolant.

It could be leaking from the windshield gasket, a rusted spot, through the cowel or roof pillar where the sealing has crack,fallen off, or got hard. The sealing comes  in a tube like caulking and is almost like bondo to fill inbetween panels to act like a seam to keep water out which can be found at any autoparts store.

Could be the door seals, door window seals, or the windshield gasket.  Leave a hose on the roof w/ the water running down the windshield and the door.  Then get inside w/ a flashlight to track down the leak.

I know on the 85 and later GL's, that they put the outside air intake below the windshield gutter system and cover plates for around the wipers.  I had a windshield repair man actually sabotage my vehicle by drilling holes through that gutter so that water would drain directly into the air intakes on both sides.  He would have done that by request from other people who like to wiretap telephones.  But that is another matter altogether.  Any ways, I sealed up the joints in the cover plates and the holes in the gutter, in order to keep water from draining directly into my outside air intakes.  Now the inside is as dry as a bone.