chevman1:
MAR-K has a wheelhouse repair flange. Here is the description:
Wheelhouse tub flange to repair rusted or damaged area of wheel tub where it meets the wood floor. 16-gage electro-galvanized steel flange has bed strip embossment like original. Instructions included. Requires 2 flanges per truck. Made in Oklahoma City, USA.
This should take you to the part online.
http://www.mar-k.com/Catalog/itemDetails.aspx?ItemID=100585

Hope this helps!