The Stovebolt Site Forums The Shop Area The HiPo Shop Exhaust manifold fasteners material type?

I like to use brass exhaust manifold nuts on standard steel studs. Real brass exhaust nuts are very tall. They cover all or most of the stud. Google for "Chevy brass exhaust manifold nuts" to see a picture. The problem is that most engines are 5/16 not 3/8. For bolts I use grade 8 steel, don't need the strength but much better steel, doesn't rust as badly and won't stretch in heat cycles. Since the threads in the block or head aren't out in the weather, a good coat of never seize will let them come out years from now with no fighting. Brass bolts wouldn't have the strength. Silicon Bronze is much harder and stronger, used a lot on salt water marine applications.

I never use stainless nuts on stainless bolts. Even covered with never seize there is a good chance of galling. Regular steel works fine because the bolt won't rust.