Here´s a quick attempt to use a 1970's (larger than the 1960's) rear window as a windscreen. The windscreen on a 1964 is made of tempered glass so there´s no legal problem to use a rear window as windscreen on a 1960´s vehicle. The 1964 windscreen is also quite low so I don´t think a rear window will block off too much vision.
The car looks quite bizzarre now! All that´s missing is a bunch of little green men in silvery suits...
