My box is at least 20 years old and weathered. It's the biggest I could make from 1 sheet of 3/4" plywood and a sloping lid. It has "parting stop" around the lid edge. I've never had a drop of water get inside.
34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.