I experienced a kind of vapor lock in slow traffic the other day so I did a few tests .Air flow equals cooler running .With a cloth over the front I ran this car at a fast idle until the tempt came up to over 200 ,I then removed the cloth but the temperature did not drop .Then I fitted this shroud and the temperature started to come down .Any one who is rebuilding there radiator and running there cars in hotter climates should consider a extra row of tubes .The radiator here is not the most efficient because of the shape of the tubes, the tubes need to be staggered not one behind another. One of my Jap cars started running hot lately, you could hear the fan switch on .When I turned on the heater it then brought the temperature right down, its almost running as affiant as the main radiator so air flow or added 10 % more radiator may do the job .