Slant Six – exhaust manifold hardware?

OK, I am confused about the end hardware for the Slant six exhaust manifold. I see pictures of the install with the slotted part of the nut facing away from the washer, but I have removed plenty of them with the slotted part of the nut facing the washer. Which way is this really supposed to go - slots up or slots down?
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Author: Badvert65