My steering linkage from SV was full of rust when I received it. Even after a can of Aerokroil and WD40, I still couldn't get the u joints as free as I felt they should be. I'll bet that is your issue. especially since one of the u joints is right above the header. Try squirting some penetrating
oil through out the u joints and see if that helps. I ended up replacing all of the SV linkage with Flaming River stuff. Their u joints have needle bearings in them.
Sydney