Crusty, I feel your pain. I have/had all the same problems with my 69 convertible. I think i'll get a license plate that reads "xrstbkt" when i'm done, ha ha. So far on this car i've replaced the full floors and also the drivers side inner rocker,fixed rust areas on the lower cowl,upper cowl,windshield area,replaced drivers side frame rail,inner wheel houses,full trunk pan. I had to get both rear floor supports fabricated because mine were toast. Now i'm working on installing the inner rear valence panel as well as the passenger rear frame rail and both trunk exstentions and drop-offs. Still a lot of metal work to go before this thing sees a paint booth! I still need to purchase full rear quarters to replase as well.I don't know why, but my convertible drivers side was way worse than passenger side(you would think they would be the same). I had to cut and section the area of the frame rail your talking about. My drivers side rail was like swiss cheese in that area.This part of the rail is not yet available in reproduction. The options would be to get one from a donor car or repair the one you have. I chose to repair mine. I would think that tubing would be a major PITA as it would be hard to align with the other side as well as installing the rear floor supports. Just my opinion. This website has been a great resourse for me and i've learned a lot. I'll help you if I can or shoot me a email at
Leahyfamily92708@yahoo.com and i'll give you my # and we can talk.
