contact someone who runs the forum. http://www.jalopyjournal.com/?page_id=2368 has an email link. Naming yourself after a car is pretty common, but might not be wise?
I think if you go to your profile you have that option. I probably would not sweat it though your user name is your online presence and not what you own. Everyone knows you as @1959 F100 it has very little to do with what you own it is just you.
No, Ryan shared about 3 or 4 years ago - that names won't change. I don't have my original Corncobcoupe anymore that my HAMB name originated from........ but it's all cool. Somebody has to be 59 F100 and I can't think of a better guy to be it than you.
It could be worse,some have joined the hamb while drinking and came up with some real winners/loosers. HRP