Mild Torque 318 suggestions wide open!

Think about running an overdrive transmission.
Stepping 'down' to 3.23/3.55 gears will make the car feel snappier during acceleration while still being able to cruise at 70-80mph at ease in OD.
Spend time working the ignition curve. Quite some torque can be found down low.
A standard 3-core radiator with fan-shroud will have no problems cooling that 318. No need to 'blow' money on aluminium radiators and electric fans, although the fans might free up some power from the engine.