Grandpa's old 1965 C10 Project

[Grandpas65]

Hello. I was fortunate enough to have my grandfather give me his old 1965 C10 SWB stepside last month. It was his daily driver until 3 years ago. Currently has a 305 V8 with the original 4 speed manual. The rest of the truck appears stock. It has a bent frame in the left rear tire area. I need to get the box off and get a better look at it, but I think I need to do a frame swap. Will 64-72' frames bolt up to cab and box mounts? Any input on the frame issue is appreciated. Here are a few pics the day I got it.