Possible Clues:

• Brand that sponsored the 'Ripley's Believe It or Not!' radio show
• Radar's drink, on "M*A*S*H"
• Classic 26-Across brand
• Fruity soft drink
• Old brand of grape soda
• 'M.A.S.H.' soda
• Nostalgic soda brand
• With 40-Across, classic grape drink
• ___ Corporation, predecessor of RC Cola's Royal Crown Company
• Soft drink brand that sounds like a long sock