So put on an 8 speed cassette and chain and enjoy the extra gears. That's what I did. You'll have to spread the rear dropouts a tiny bit (4 mm) when you install the wheel. If the cassette body is Shimano, you can buy a 105 cassette for pretty cheap. If it's Campy, Veloce is fairly cheap too. If you're going for "period correct" restoration, then ignore that advice.