71 Twister with 340 4-spd, Bent front frame rails

Hi, I am new to the forum.
I recently bought a 71 Duster Twister, on Ebay. It was converted from a 318 3-spd manual, to a 340 4-spd. It's a really cool car, and has plenty of small issues. However, after doing some investigating into why the body panels don't fit properly, I discovered the front frame rails are bent. I have an excellent body/frame guy, who says the best way to fix it, is to replace the front frame rails. He said he could put it on the frame machine, but it would take much longer than replacing them. Does anyone know where I can get some frame rails? Does anybody make aftermarket replacements?

Thanks,
Brian