[Jack21]

These Split Locks are probably the cure for header bolts that tend to loosen.

Fortunately, mine don't. CR factory headers have a fairly thick, one piece flange, and are ceramic coated. sed the FelPro copper gasket, and some copper RTV to seal 'em up. Used ARP header bolts which incorporate a lock washer, and they've stayed tight.

Header to "J" pipe uses factory composite gaskets, copper RTV, hardware store stainless nuts, bolts, and lockwashers and they stay tight also.