GMC Trucks porcelain sign is a must-have for any collector of automobile advertising especially gas and oil memorabilia. It features the recognizable GM truck with large lettering across the top. Whether you are displaying this sign as part of your collection in your man cave, shop, bar, or garage, or giving it as a gift, you can also browse my other auctions for more vintage gas, oil, aviation, automobile, motorcycle, and hunting signs. GMC Trucks & Automobiles. 12 inches in diameter. Bright colors w/ porcelain on both sides.