Try calling Stage 8 directly, 1-800-843-7836. They have other shapes besides the "half moon" tabs that come with the header bolt kits, you might have better luck with something else.

 

i got regular lockwashers with my flowtechs.. but only 6 of them.. i soon realised that i could only use the washers on 6 of the bolts.. i just got the headers nice and hot, cranked them down and never had any back off.

maybe it's because i don't put many miles on mine. i've got 4500 miles on this engine and it got put in the car 5 yrs ago

 

I'd tend to agree Shifty allthough the picture is proof. My standard ARP bolts were a tight fit with the flowtechs a locking set would have drove me insane in a few spots. But seriously even if you use cheap bolts with the DS aluminum gaskets the bolts dont come loose because the gasket doesent break down and allow them to loosen up.