These brass nuts will not seize up on the studs, if you've ever broke a stud off, you know that is big trouble!
1956-1979 Brass Nuts For Exhaust Manifold Studs play an essential part in holding the front exhaust pipes to the exhaust manifolds. Replacing the Nuts ensure the seal between the manifold and the front exhaust pipe does not leak and create unwanted noise.
The purpose of brass exhaust manifold nut are to avoid corrosion and the bonding of the nuts to the manifold studs.