Just finished the pass side floor yesterday. Floor pans are fairly cheap but it’s a lot of work to put one in for sure.
The cars are made and assembled as UNIBODY construction. Every panel connection needs to be properly welded to support the load. I bunch of old rust panels held together with road sign material and rivets and/or adhesive won't keep your car together for very long.
Been there, done it. I kept my coupe car for over 30 years before I attempted to do the 2nd restoration Opened her up and nothing but rust.
I got the vert professionally welded and it turned out great. Even measured the chassis and against the body and it was very close to GM required specs.
DO it right or sell it...save your time and $$.
