Other than being a specific length, I believe they're just plain old Grade 5 bolts. Snug both manifolds onto the cylinder head before tightening the bolts all the way, allowing the best alignment between both manifolds and the surface of the head. Lots of KROIL and some heat helps to get them loose without breaking anything.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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