[CompClassics]

patrict,

The major advantages of an all metal lock nut are resistance to heat and the additional metal thread of the fastener given the same fastener depth of the Nylock nut, you’ll gain griping material. The Nylock nuts will give you no mechanical advantage in the nylon locking area.
Jet nuts are a fairly modern design, back in the 50s and 60s Flexlock nuts were the norm in the aviation industry and also in the race car community, sort of a trickledown technology. SAI used aviation Flexlock nuts and aviation AN bolts on their competition Cobras in critical areas like the driveline and chassis components.