68-300 Unibody options

I have a 68-300 convertible. I’m looking for a rust free unibody and stub frame… front to back if available. I’ll take it in sections if available… also rear wheel wells.

Considering this, Im trying to determine what other cars (years, models) have the same, or similar enough… unibody and stub frame. (Newport, New Yorker, Imperial, Fury, Polara, etc)

Thanks in advance
Author: LDarling2