69 dart front frame replacement

Dad and I are starting in on this 69 dart I bought. First order of business is the driver side front frame rail is rotted from a battery leaking on it. We need to replace the front rail. But unless I'm blind, I can't for the life of me find a new replacement anywhere. Not AMD or anything. Anyone ever use one of those caps? Is that my only option for new stuff? Do I need a donor rail? What has everyone else done? Thanks fellas
Author: admin