NASCAR Racing: pit sign, collectibles market, collector cars

Question
i have a pit stop sign with the stp logo on it.no dought pettys pit. my grandma got it from a race in 1970-1975 not sure yet.would it be possible. to authenticate it.i have pictures of her at the race with the sign.if so.what would it be worth to collectors

Answer
As far as authenticating it, the pic from the race should be a pretty good way. As for the value, something like that is not easy to put a value on. It is a "unique" item, one that you don't see every day. The collectibles market is very volatile with items only being worth what someone will pay for it. I get a kick out of so called "collectibles values" books that give false hope of giant dollars for collector cars or cards. Try to get those prices and you'll be in for a bad surprise.
The only true way to find out is put it up for sale at an auction. Get a couple that just "HAVE" to have it and you'll get a lot. Nobody really interested... you'll be disappointed. Put it on eBay and you'll find out just exactly what it's worth.