I have a Mitchell interchange book. It lists three different fuel tanks used through those years. Two of them are listed as 24 gallon tanks. Probably all three are. but there are two additional choices for you. The 68-69 vetts had a 20 gallon tank that will fit if used with the mounting straps, and a 36.5 gallon tank also requiring the straps. I would suggest contacting Mid America Corvettes for more exact info when changing from original. Good luck.