Shift Arm Replacement Process
You asked what's involved and it's a pretty big job. In a nutshell;
You will need to pull the steering wheel, then the shift collar (replace this if it is at all worn around the roll pin), disconnect the turn signal switch and neutral switch wires (label the wires you disconnect from, important to also mark the position of the neutral switch before loosening it), then loosen the firewall weather seal.
Next you will disconnect the steering column from the clamp under the dash. The shift tube and selector arm will now slide out leaving only the steering shaft in place. Before you put the news arm on, be sure that it fits over tube and locking lug with just enough clearance to allow it to slide up and down smoothly, but not as loose as the old one! This is critical.
While you have it apart, you should also replace the shift detent plate if you haven't already. A new shifter lever arm and roll pin would make it all the more likely to achieve the results you would be happy with. I did all this in about 3-4 hours...only a little cursing, actually a lot.
You can contact me offline if you have additional questions (firstname.lastname@example.org)