1955-1959 Oak bed wood – GM Truck longbed stepside 89″ we guarantee wood to be of proper fit. the wood is guaranteed for 14 days from ship date. for this reason you should wait to purchase wood untill you are ready to install. oak is fas or face and better grade which means that the top face is free of defects. pine is grade c which means that knots in wood are maximum 3/8 firm.