[Gunner]

It's a splitter. They are quite common in street performance cars with a deep, open radiator inlet. My ERA has one. You can see them on many modern "scoop nose" cars as well.

I am not entirely clear on the theory but in general, breaking up a large opening with a blade like this promotes cleaner, stronger flow into the radiator instead of allowing the air to burble around in front of it. They aren't used on race versions of cars because at track speeds, the air gets rammed through no matter what. Taking the same car to the street means that at lower speeds, the air can be so turbulent that hardly any flows through the radiator. The splitter helps to prevent that.