I have a very stupid question. On my 66, I have an area that is ate out at the bottom of the quarter panel, in front of the rear tire. It goes from where the door ends to the wheel well. Does the rocker panels go from fender to fender? In other words, instead of doing patch work, could I just replace the whole rocker? Does is cover that far behind the door?

Not a very stupid question.
The replacement rockers cover the whole length.
Might be best to replace the whole rocker, as I would expect more of the rocker to be weak.

Thank you Wiley, that is what I preferred to do. I looked like it was all one piece, but I did not want to buy the whole rocker if it was not going to reach.

Thanks again.

I bought a repo rocker for my 67 to section in a foot long section that was bashed in in the middle of the door. I cut my bad section out but the repo rockers profile was all off and I couldn't use it. I was complaining to my GTO buddy about it and he comes back from his barn with a 1965 GTO used rocker he removed from a rust free goat. "Try this". It fit perfect!!

If its under and in the back you can replace just the inner rocker. paddock.com sells them