I have a 59 small window & installed one of these last year. It will fit yours as well but its very sensitive when putting it on. If you put it on like being in a modern car/truck it will lock. If putting it on very slowly annoys you ....I'd look for something different, maybe a factory one from the bone yard or ebay.... Just my 2 cents.....good luck.

https://www.classicparts.com/47-59-and-67-87-Shoulder-_-Lap-Belt-Black/productinfo/28-071/


1959 3100, original 235/3 on the tree w/overdrive. Carter YF 2100S carb, 205/75/15 w/front sway bar