Stud that attaches exhaust manfold to exhaust pipe

[keithert]

One of the studs that holds my exhaust manifold to the pipe that goes to the catalytic converter is broken. Does anyone know what size that stud is? Would NAPA carry it? The one that is broken is the upper one so there is limited space to work in. I hope it can be replaced without having to remove the manifold. If I get the old one out should I just use a normal bolt in its place? The manifold is new so the old one is not rusted in.