Hola John Every now and then we get a question that has a unknown for a starting point. If John had said for his 68, I would have said..." Try the Autolite's # 86". ( The reason for # 86 instead of the # 85's is the engine will burn off better if the miles are a little high. Rodger & Gabby 63 Le Baron w/86's 66 Le Baron w/86's