Nylon lock nuts on exhaust flanges?

[Qyota]

Stupid question, probably. Is there a locking nut that should be used on exhaust flanges? I ask because recently I used stainless steel nylon-insert lock nuts on my replacement exhaust. I checked them today and the nylon is still there (I feared it would melt quickly), but it is now clear instead of white!

In the hardware store I saw stop nuts (the oval-ized kind), and of course split lock washers as the alternatives.

What's the best way to keep flange bolts and nuts together?

Thanks!

 

[toytech76]

You can get exhaust nuts from toyota. They are like you said sort of avalized and have a flange to prevent backing off