The 1967 had a mono leaf spring where the 68 had a multi,Which I am sure you know but if you ended up with a 67 it is a thicker pad also DON'T use a impact!!! tighten by hand in a oppisit (x) end pattern and watch the base if it starts to bend if it just starts your there. stop. also make sure the bumps on the pad are correct if they don't line up it will put a stress on them.Hope this helps