[Davidf]

Originally Posted by ls1nova71

Does the engine have 706 heads? If so, could be a set of Castech heads that were known for cracking.

Also, the '98 coolant temp sensor may move the gauge in a '72, but won't be accurate. Tried that 20 years ago on my '71 Nova, which I'm sure uses the same internal gauge parts and it didn't work.

No, 862 heads. Could not find the Castech foundry mark. Part of me is starting to wonder if I have a head gasket leak. I think I will pull the heads, inspect and then take the heads to the machine shop as I will want them freshened up regardless. The shop can pressure check them for me.