I use the Nordlock 3/8" washers on my engine in combination with remflex gaskets, hooker headers and Eddy heads. No header bolts coming loose and no leaks after five years.
Having both remflex gaskets and nord locks(how much thicker are nord locks verses standard lock washer?), were standard length header bolts(or studs) long enough to get a adequate bite into head threads? Having aluminum heads, this could be an issue so as not to strip out threads.
I would guess that upon initial installation a secondary torquing of bolts is still required after a few heating/cooling cycles.
