[67c10rustbuket]

The upper extensions were original on all automatics but they get removed over time by people who dont want to fight them upon re-install, thats the case I have seen anyway. They tie the crossmember to the upper side of the frame rail for extra strength. I noticed in the link from lockdoc that one has the exhaust clearance humps and one does not like the link I posted. Too many strange differences and hard to determine if they are 73+ or just a wacky 67-72 difference. I personally have an aftermarket trans xmember because my truck was a 3ott and was not equipped with an auto x member.