Let's see if this helps out a little. I just got off the phone with ARP, regarding the issue of SS vs CrMo exhaust stud/bolts. ARP uses a propietary 300 series SS for their studs and bolt as well as their head and rod studs/bolts. It has a 170,000 psi tensile strength and is impervious to extreme heat and corrosion. They also offer a 8740 CrMo version of the exhaust studs/bolts which has a +180,000 psi tensile strength. These have a black oxide finish and provide much less corrosion resistance. I ask their tech guy if they recommend any special thread prep, when installing exhaust studs or bolts......their recommendation is to first insure the threads you intend to install the studs or bolts into is cleaned well. They use a molly lube or 30wt. oils for installation and do not use a thread locking agent. So, I ask the guy which material is better for the exhaust studs od bolts? I'm told either material is good, but if you want corrosion resistance go with the SS. I also asked him about the thermal expansion characteristics between the two materials and he came back with....Well, we use the SS for head bolt/stud as well as rod bolts, which are much more tolerance critical (as far as thermal expansion) than exhaust studs or bolt. So, here it is staight from the horses mouth (ARP). Draw your own conclusions on which material you think is best for your application. Me, I've been using their SS exhaust studs for years without any issues...but that just me. Hope this helps a bit?