I believe the OP is asking about the Cobra 427 jack hook orientation, which is different than the leaf spring cars. If you're after originality on a small block comp car as completed by SAI, usually the quick jack's were mounted to the frame and the body modified to accept them. Normally spacers were not used. They were mounted using AN bolts, heads exposed and didn't use threaded rod or studs.
They don't show very well in this photo but you can see the body modification around the jack hook.
Larry