If both cars are of equal value, this is what you want and the other guy is willing to trade I'd say go for it. I don't think you're going to lose anything by doing this.
Both cars are plentiful, being remanufactured/ supported by aftermarket/ available for sale all day long, and when I look on sites like "cars on line" I see Camaros listed in broader price ranges which tells me there is a greater overall market for them (something for every wallet). Plus the fact they are still very popular in media, movies, toys, etc which has worldwide exposure to people of all ages. This tells me that their awareness and value isn't going away anytime soon.
Willys cars, on the other hand, are really niche to the drag racing & street rod crowd, IMO. They have a much smaller fan base overall and are out of reach to those without the deep pockets to buy into them. At this point in time I think the future value of cars in this realm are in jeopardy unless they can get the next generation of hot rodders interested in them.
My 2 cents on a 2 year old thread