The best thing to do is to get a kit to french them in. Here are a couple that I found online.
http://www.classicindustries.com/con...rchCatalogId=4
http://www.classicindustries.com/con...rchCatalogId=4
Now this place has a ton of stuff for these trucks. I have a 55 Chevy Series one pickup that I am going to be building and I am going to be getting a lot of things from these guys for it.