Cyl Temp Possible Issue
I wanted to add to this. I thought about ordering one of the Cylinder Head Temp gauges that you mentioned. After doing some research, I found out that that gauge setup is intended for air cooled engines. I would be willing to bet that it would work with a Ford V8, but with tapered seat plugs...it might be tricky. I think that these are used in air cooled VW's and Jr. Dragsters and stuff.
If you do find a way to work it though, let me know...not that I need ONE more gauge though
I am glad that someone mentioned this and brought it out.