Does this product go over top of the old frame rail? Or do i have to actually cut out the old one then install this? I'm in a tough boat because i was in the process of replacing my radiator core support when i realized how rusted my frame rail actually was so now my core support is out and not sure of how to go about replacing the frame rail.
These are actual replacements and not caps, so you can replace it entirely, or use a portion of it to replace the rusted portion if it is isolated. It will require cutting and welding for proper installation.