Changing the switch aint hard but alot of work. On my 76 I have to drop the steering column to get to the 2 bolts holding the switch in place on the column, cant get to it otherwise. Remove those two bolts holding the dimmer switch and ignition switch in place unplug and replace, do the reverse to get it back up.
One thing though, operate the key switch after you tighten it to the column and BEFORE to put the column back up, you need to position it so that you get full swing from off to start position. Just operate to key to make sure nothing is binding and be sure you get from off to start with no problems.