Originally Posted by Silver-Bolt

As a fastener guy you really don't want stainless hardware on your exhaust. On the collectors the cheap old grade 2 stuff is the best. Easy to twist off when it's time to remove. Plenty strong to hold everything. Stainless will actually "weld" itself together with the heat. Talk about tough to remove. The zinc plated stuff will end up rusting at some point but it's cheap and easy to replace. On the headers either plain steel or zinc/cad plated is the best choice. Threading a stainless bolt into an aluminum head is a very good way to create galvanic corrosion. The only thing you really want out of 300 series stainless are the headers, mufflers, cats, and tubing. Stainless washers are fine but not really a benefit.