Magnum exhaust manifold studs.

Worth a shot, all they have is fully threaded 5/16 stainless. I could just buy some 5/16 stainless threaded rod from Lowe's or home Depot. Does anyone know if the bolts holding the manifolds have to be a finer thread on the rods?
I'm guessing no, because the rest of the bolts will all be 5/16 x 18.