I found this out the hard way also. Remove the valve cover, you will see that the rear rocker arm support bolt is in perfect alignment with the temp sender and if someone installed too long a bolt it will hold the temp sensor in. Sorry for the bad news.
Bob, Are you going to Spokane? I know it is a little late as I am leaving in the morning for Spokane. What car are you driving? I will be in a maroon 52 Buick woodie wagon with Oregon plates.
I have a 66 turbo 400 Buick transmission behind a 425 nailhead. I had the switch pitch torque convertor rebuild. Can I drive it for a 1,000 miles without hooking up the switch pitch assembly? Which position is the torque converter in if not wired up to electricity?