Yes , ThermoCure works nice. Have had some heating issues in my 98 but not in the 88 .
Here is a pic from the 88 engine who is at the machineshop now. Plug between cyl 5 and 7.
And also crap in the hole the other side between 6 and 8. But no heating readings on the gauge.

Somebody in Californa have also removed the heat riser in the exhaust manifold.

 

Did that freeze plug rust out?

My 64 98 had one of those heat riser valves in the exhaust manifold. It was seized partially closed so I knocked it out.

 

No the freeze plug did not rust out. I suspect
that it looks the same in the 98 engine. The heat
riser in the 98 work bad so i forced it open with
a wire. But should remove it when it can.

I should put a tempgauge in car before summer ,
the 88 have a mechanical gauge that works fine.

 

I moved our posts so we didn't hijack the other thread.

As mentioned, don't fall down the temperature gauge rabbit hole. That being said, if you decide to go with an aftermarket gauge I have 3 AutoMeter gauges in my 86 Ford truck. They work great.

 

Ok Jesse , well the red light have come on a couple of times when we drive slow cruising but we have not done that for a while. I don't mind having a gauge in the car .

Have three SW gauges in the 88 and they work great.