8333 x 8. Set of 8 of our Excellent EXTRA LONG brass nuts that conceal twice as much thread to prevent fouling from corrosion. For the cast Manifolds lower end stud to the Exhaust  Down Pipe flange. This longer nut covers and  protects the delicate threads for easier removal,  as this is a common failing point for the exhaust at this flange joint gasket (SEE : 8260 ) and any  mild steel in exhaust systems are known to corrode badly.

Original Ref. Number NN137L