Magnum exhaust manifold studs.

Where can I find some magnum exhaust manifold studs. I've been searching all over the place, and I cannot find any studs long enough. I ordered some from Amazon that said they are 2.5 inches long. I figured that'd be long enough as the exhaust part where the manifold studs go is 2" long. I figured 1/4 inch in the head and 1/4" to bolt on the other end. But when they arrived they were only 2/14" long. I could get some la ones and put the studs in the two inner locations I suppose.