What size bolt do i use for my seat belt bolts?

you use a seat belt bolt with a special head, shoulder and hardening.

Don't know what the size is, but the bolts themselves are slightly different, depending on where they go. You can check them out on Year One's web site (http://www.yearone.com/serverfiles/headline.asp?hid=011AD47768), but places like Autozone could have them as well. The shoulder is different, depending on what it's used for, for example if it's used to hold one, two or three belts (like for the lap belts on a bench seat). I'm sorry for not being able to be more specific, but a call to Year One might be a good idea.

thanx