Classic/Antique Car Repair: New bulbs for classic car 1968, auto bulb, courtesy light

Question
I have a '68 Skylark convertible. I bought new bulbs. Number 90 for courtesy light.  It won't go in enough to twist lock.  I ground down the contact nubs and now it reaches the bulb body before it can turn.  Also the license plate light same thing, however I ground it enough to reach.  Is there a source for more accurate bulbs or a fix that I'm not thinking of?

Answer
First check and see if the contacts on the old bulb and the new bulb are the same.
There are two kinds, parallel and off set (one higher than the other)
These bulbs are just one product number off from each other.
the courtesy lights have two different bulbs #90 AND/OR #89.
The license plate bulbs are #67 AND/OR #90.
If you have your owners manual look up the bulbs there.

Here is a link to a good source for all your auto bulb needs.  Let me know if you need more help.
http://www.sylvania.com/ConsumerProducts/AutomotiveLighting/LampReplacementGuide...