The side rails of this frame I just picked up for my 67 are slightly bent upward in a couple spots. This Im sure is from the car hitting curbs and or bottoming out over the years. Its a bit pushed up or dented just under where the driver and passenger sit - not a big deal - the frame is mint otherwise. I want to fix these areas before I blast and paint the frame.

Also a bit dented upward is the back frame rail behind the rear wheel - along the passenger side. How is the best way to fix these and get them straight again? Is it doable without going on a frame machine. I had a body shop attempt to fix my original frame and they made it much worse.
I dont want to even have a shop touch this one if I can avoid it. Any suggestions on doing it myself would be very helpful. Thanks - John

Is the frame bent or is it dented on the bottom?

If it is bent you have to have a frame shop straighten it.

If it is dented a frame shop can pull the dents out but you would still be able to see where they were.

I know of people who used body filler to smooth the frame before they painted it. I would not expect filler to last on the bottom of the frame.