Vredesteins are the way to go - they handle great and are pretty cheap! I have a set on my '65. This is where I bought mine:
Vredestein
If you are looking for uber performance that will make the guys with 9" wheels cry, you could go for the Avon CR6ZZs, but they wear out fast and are over twice the price of the Vredes:
Directory Listing of /racetirepricing/Avon Race Tires/
They are, however, the best performance tire on the market for 4.5" x 15" fitment.