440 Dart cooling fan & shroud

George,
With what you have for the lower pulley I think you'll need an electric fan setup. And a good one with a shroud. It's not a good idea to put a fan on each side... they tend to cause turbulence over each other and both lose affect that way. Two smaller fans are much more efficient. Use a thermal switch to control them, and upgrade the wiring and relays to power them, and they are as reliable as any mechanical setup.