I am installing a new long branch header. I am using new Grade 8 bolts with washers and locking washers. Do I need to put any anti sieze lubricant on the threads? Conversely, do I need a thread locker? Or should I leave the threads alone, i.e. dry?

Thanks.

I would use manifold studs with extended brass nuts. You can use antiseize where the studs go in the manifold, but it will probably burn out anyway. Recheck torque on brass nuts after first heat cycle.

Oh, you meant manifold to head... sorry. I sometimes use antiseize.

Thanks for the tip. I'll be getting to the pipes next.

I second the studs and brass nuts for the pipe. Be really careful and don't over tighten as those cast pipe flanges are somewhat easily broken.
I would also prefer anti-sieze over loctite, but by rights you shouldn't need either.
The long branch manifolds are really neat.