About 20 years ago, a Buddy and I bought these boxes from a rural Chrysler dealership (Pigden Motors) that was closing shop. They had been in business since the early fifties. These boxes were shipped from Chrysler to all the dealerships probably 6 times a year, and they contained all the advertising and promotional stuff that was needed to convert a complete dealership's theme for that particular time of the year. These boxes measured about 40"X30"X3".
If I recall we ended up with about 12 boxes, or a couple years worth of promo stuff. Here's the best part, they were from the mid 50's, and were never opened !!! It was like we were opening time capsules. The boxes contained large posters for both the showroom and parts dept. They also contained weird stuff like bags of balloons with advertising, and even 12"dia 16mm movie reels. I remember borrowing a projector from the library and watching these "new" 50 year old movies. I still have a small box full of the smaller items, but haven't looked at it in years.