[storm9c1]

I just use grade-8 bolts of the correct length and thread these days. I've had good success with both hardware store (zinc coated) and automotive grade flanged bolts. No need to overcomplicate it. In most cases, you can use studs with nuts too. Studs especially help on aluminum heads since the stud can/will seize in aluminum but the nuts can be more easily removed. Studs also help lining things up during reassembly. I think the last set I used were ARP (expensive, but I had them in stock left over from another project). Studs also help hold the gasket and help guide the manifold on. But be careful though, some vehicles are so tight that adding studs prevents the manifolds from being slid into place. It can either help or hurt you.

On some engines with iron heads, I've used stainless steel bolts. They aren't as strong but are easier to drill out (than grade-8) if they do happen to break. Harder to weld to SS as well, so choose carefully. Needless to say, you have many options.