I have to agree that it sounds like you could use new bushings on the shifter lever. I did mine last week, and it made a world of difference. It feels much tighter. Doug's right on making sure the lever is pointed forward. It's not a complicated job, but cramped for fingers, and if you also put new bushings where the lever meets the main rod that goes up to the tranny, it's a tight fit to get the bolt back in there. I.e., not something you'll want to have to take apart to redo.
Rick
Dallas TX
1967 250SL, 4-speed