Originally Posted by mrfreeze
Unfortunately, I did learn that my door locks which worked smoothly when I got the car over a decade ago now will not allow a key to be fully inserted so they may need to be replaced. I tried spraying some penetrating oil in the door cylinder that I removed but so far it hasn't helped. I think I can get the door locks for about $12 each on Ebay but it is unlikely that I would get a matched set. There are options for matched sets but the prices go up significantly. This won't be an urgent issue until the car is painted which isn't going to happen any time soon. The main concerns were getting the trunk open & being able to use the ignition switch when the motor goes back in.
Try putting some penetrating oil in a cup and let the locks soak for a few days. I would be shocked if the tumblers didn't free up. That's the only thing that would keep the keys from being inserted.