The Stovebolt Site Forums The Shop Area Paint and Body Shop Truck body reassemble sequence ('46 Chevy 1/2 ton)

You should be able to see the about 1/8" inside diameter drain holes, one in each lower corner of the windshield/cab frame opening. With the kick panel removed on each side, look behind the "A" pillar for a copper tube that extends from the top holes described and leading down to and passing through a hole in the front cab corners. It's possible the tube may not be aligned with the bottom hole after this many years. Sparky's were not and the holes at top and bottom were plugged. If you still can't find these, send me a PM with your email address and I'll take some photos to send you.

Edit for additional info: There is a short rubber hose that connects the 3/16" OD copper tube to the short, about 2 inch long tube at the top hole, on each side. The copper tube is held in place along the "A" pillar with two pliable clips each about 1/2" wide. The bottom of the copper tube passes through, barely, a hole in the outside corner of the "A" pillar.