Its just as easy and cost effective to buy a lock set and replace all of them. I have modified tumblers before, the problem is the tumbler covers are swaged in so its hard to get them apart. A locksmith can make a key for a lock without removing the lock but I would guess the end cost will be close to what a new lock set would cost. If that has tilt steering it may be hard to find a ignition lock because they are different and im not sure if that is repopped.
