Exhaust Header Flange to Manifold Nuts

[Steve Junkersfeld]

My 56 has three bolt exhaust manifolds. I have seen two types of nuts that retain the header flange to the manifold stud. One is a long (maybe 3/4") bronze or brass nut and the other is a more standard looking, crimped, self locking nut. Any ideas on which is correct for my car? Thanks Steve

[Joe L.]

Re: Exhaust Header Flange to Manifold Nuts

Steve-----

I'm not sure on this one. However, I think that the nut used was a more-or-less standard thickness brass nut of GM #838780 which are still available from GM. The self-locking style nut, GM #3829086 and which is also still available, was used on most C2 and C3 but I don't know if it was used on any C1. I believe that the long brass nuts are aftermarket. However, from a functional standpoint, they are all that I, personally, use.