Two years ago a good friend of mine did up a 60 Impala Convertible he bought in PA. It had a 348/4V and a 4 speed. The tripower carbs were also available in that year.
On a side note, since he had helped me with some stuff in the past I offerred to buff all his stainless trim. Any idea how much trim is on a 60 Impala? Seemed like miles of the stuff