74 dart swinger shell

I am looking far a 74-76 swinger or scamp that I can use to rebuild my 74 swinger into. I have had mine for 20 years but it's too far gone to repair anymore but the interior and drivetrain are good as well as all the trim. I would prefer a car that was originally an a/c slant six car but rust is the biggest concern. I want the rebuilt car to last me another 40 years at least. I am located in Ontario.