I had a little mystery that’s half solved at this point. On the 67 I just got, the parking brake light on the dash will start flashing after about 10 seconds. I thought, that’s cool, does my other 67 do that? Well, it doesn’t. The flashing is not aided by a flasher, can’t hear anything clicking. After a quick search through FSM I see the bulb is a 257. Search on the web shows there are flasher bulbs. Never knew there were bulbs with built in flasher! Nothing in the FSM about the bulb being a flasher. Question is, did someone put a flasher bulb in the car at some point or did these cars come with a flasher bulb? Does your 67 R/T park brake lamp flash?