I am wondering if anyone has tried to fit a modern split-bench front seat and modern back seat into their 1963-64 GM B-Body (LeSabre, Impala, Dynamic/Jetstar 88, Catalina)? I’m considering buying a basket-case ’64 Oldsmobile Dynamic 88 convertible to turn into a mild custom and am interested in putting more modern seats in (with lumbar, maybe integral seat belts, etc). Mild floor fabrication to make the seats fit is OK with me (the car is a basket case and needs some floor work). Anyone taken measurements to see what might fit?  I would think that someone has looked into this for their Impala...