I'm a big fan of stainless hardware, it's similar in strength to grade 8 and it won't rust. And you can definitely find flanged stainless hardware, though maybe not in local hardware stores. If you're planning on doing headers down the road though, I probably wouldn't spend the money on it since they'll require different hardware.
Edit: now that I think about it, I think stainless normally falls somewhere between grade 5 and grade 8 for strength. I still think it's probably strong enough, it's completely fine with headers, but I wonder if the different thermal properties of the stainless and cast iron could cause enough of an issue to break them with repeated heating and cooling cycles if you used them with factory manifolds. I kind of doubt it, but I'm not a metallurgist either.
The stainless hardware found in hardware stores sometimes isn't even grade 5. I wouldn't use anything stainless unless you get it from a reputable source like ARP (or totally stainless, which seems to mainly source from ARP). With that said, those brands have stainless hardware that exceeds grade 8 specifications and is safe to use on all sorts of applications that hardware store stainless would never be safe for, like brake and suspension parts. I hear of marine engine guys using them all the time in exhaust manifolds, but those guys will also caution you not to use any sub par stainless or you will run into fatigue issues causing the bolts to eventually fail after multiple retightenings as they stretch.
I never thought of that, just outright changing them every few years. That would pretty much solve the problem. Just making sure you install a quality replacement, and use some anti-seize on the threads as well.I ran grade 5 exhaust manifold bolts for years on my B-bodies, just changed them out every few years and never had a
using grade 5 bolts that is why you do the changing every few years IMO not good idea.I never thought of that, just outright changing them every few years. That would pretty much solve the problem. Just making sure you install a quality replacement, and use some anti-seize on the threads as well.
+1 on the recommendation!