lower radiator panel

[mr48chev]

It doesn't block the air flow at all but directs it up to the radiator. And it does add a lot of structure, especially when mods have been made to the other pieces. All of the pieces in the front ends of these trucks work together to make the whole structure sound and when one is missing or compromised it allows for the front end to flex.
Over the past 39 years I've made about every mistake that can be made with one of these trucks and leaving pieces out of the front end sheet metal and having problems later have been high on that list.