Lock washers will not retain their "lock" with the heat cycling on exhaust manifolds.
So they are not used on exhaust manifolds?
'69 RS Z/28 Olympic Gold, 711
Flat hood no spoiler, black top, endura, 4:10
69 X77 Z/28 69 711 Original Paint Unrestored
'69 X66 Convertible Cortez Silver 712 black top Endura, auto, bumper guards, am/fm rear speaker 44k miles