Call your local bodyshop and they will tell you who local to you has a frame machine and would be willing to do it for you , plan on $350.00 just to set it up on the machine and then it's just $$ by the hour . As long as the frame doesn't have any issues other than being bent *rust* it's way faster and less expensive to save it . Use the search box ^ and check out Chevy lean ,It's pretty common on these old trucks.