Do you have the new lock cylinder with you? I find it easier to change if I have a loose one in hand. On the loose cylinder you will see a release keeper. This keeper can be acceseed by punching though the pot metal in the column with a screwdriver. By measuring the cylinder from the end to the keeper, you will have a good idea where to punch the column.
I believe you need to remove the turns signal switch assembly also to get at the spot where you will depress the latch on the key lock assembly. YOu don't need to remove the switch from the column, just remove the screws holding it and with the wires unplugged pull it out 6 inches or so to expose the slot where a thin screwdriver will fit to depress the latch. My chassis manual for the 69 says you can remove the lock cylinder assembly in any postion, lock or run, but you need to depress that latch to get it out. It will be pictured in the chassis service manual.
A forum community dedicated to Chevrolet Chevelle owners and enthusiasts. Come join the discussion about restorations, builds, performance, modifications, classifieds, troubleshooting, maintenance, and more!