Here's a 1966 F-Series pickup.
http://www.imcdb.org/vehicle_64825-Ford-F-Series.html

I guess it was caused by OVH. I hope that it will not re-happen too often.
Next time if that happens again if I have time I'll make tests to find what causes it exactly.

I had the same problem yesterday. I could not log in. But everything is working fine today

Check the "auto login" option on the login page (do not forget to logoff later, if you use a shared computer, or go delete the imcdb cookie in web browser's options).
I do not know exactly what happens for the moment, it seems that there is some problem which happened yesterday, but as I did not change anything I have no idea of where the problem comes from.
I'll have to try to solve that though

No, I didn't. I am using a shared computer right now, but re-booting it wouldn't be such a bad idea.

Have you tried re-booting your computer? That always works for me when I cannot get on to the site

Currently, I'm having trouble logging into the main site for some reason. But since I can still get through on the forums, I'd like to point out that now that I see the grille of this Mid-1960's Ford B-500:

http://www.imcdb.org/vehicle_116217-Ford-B-500-1963.html

I can tell you the exact year is a 1966.