295 is the width of the tread , so it depends how tall you want the tire to be , most use the 275 60 15 which I think looks too tall on an E body , but there is almost no other choice in 15" , I found a 275 50 for my car which is the same width but approx. 2" shorter
Once you go into 17 " you have a lot more choice so a 295 50 may be tall enough if you go to a 45 or 40 series the tire becomes shorter , any good online tire store should have listings of the different widths & heights of the different series tires