I wouldn't cut apart a cab trying to convert it to big window or small window. It can be done but with a lot of work and patience. If you do have a big window cab Do not cut it to replace with a small window. then look for another cab with a small window.
I heard the reason why there are so few big window trucks is because in those days with no A/C it got to hot in the cab with all the sunshine shinning in.
