Are you thinking that somehow my engine has parts that don't match the parts list for a V8 300 C-A engine.
Not sure what to think. Things were changing soo fast during these years, support material couldn’t keep up. This is why techs are trained in how the systems work, so when we get conflicting info we can find were the answer is.
The diagnostic manual for the 2 serial numbers you have posted shows this engine as using 2 EGT sensors to monitor riser/elbow temp. They don’t even list the 441,442 codes.
The wiring diagram is the same for both S/Ns. It shows 4 temp sensors. None of them EGT sensors.
The parts breakdown is kind of iffy for this engine. It shows 2 temp sensors. It also shows that if you wanted a TPS you would have to buy the complete throttle body, sure hope that’s a typo/glitch. Also shows that if you want replacement heat exchanger cap gaskets ---- you have to buy a heat exchanger? That’s crazy because when you service the heat exchanger on this engine, you remove the end caps and clean it out. You only back flush / chemical flush sealed heat exchangers.
I’m not sure what your engine has. I can’t see your engine. The only question you’ve answered is what the FMI numbers are. At this point I’m not even sure if your manifolds are raw water cooled. Have you loosened any hoses to see what comes out? The only way anyone can help you is if you answer questions 100% correct. If you’re not sure, just ask and we can help you.
did you post a pic of the O2 feedback monitor? ERWT sensor temperature and voltage information is only available in Diacom’s O2 Feedback Monitor.
A lot depends on what you have. Do you have a Temperature Control Device (TCD) or a Pressure Control Device (PCD) and what one do you have?
Maybe post a pic of what you have? I would hate to give you advice on how to service a TCD if you have a PCD
Your engine may have 1 or 2 temp sensors on each manifold, they will look the same. Do you know how many you have? They will have 1 or 2 wires.
If you look at Diacom do you see temps for EMWT and ERWT?
Like I said a couple of times before.
The temperature control devices are the most common cause of this problem. They are also the easiest and cheapest to check.
Could the problem be somewhere else? Sure could, might even be electrical (you said earlier something about shooting the manifold temps—did you?) maybe do a clear hose test, maybe a total water output test, maybe inspect the heat exchanger and replace the rubber cap gaskets --- they tend to start to go bad at this age and expand so they block the water flow.