Firestone 721s are still available from time to time. Apparently they do a
run of them every so often. I just ordered a set this week from an online
source, Tirenet.com, for just over $80 each. I was concerned about the
Firestone brand at first, but John at Tirenet assured me they were a very
well built tire and the best choice for heavy cars as they have the heavier
load rating, yet will still give a soft ride. I have used Broadway Classics
before when the Firestone's were not available, but do prefer the name brand
(even if it is Firestone) to some off-brand tires.
John -- 78 NYB