High Temp, Clear Coat ??

Here's a question that will have some of you shaking your heads but as I was working this afternoon scraping decades of crud off my replacement engine that I wanted to repaint I had the idea to clean it really well and clear coat it instead. The rest of the truck will be a rustoration and I got to thinking that a freshly painted motor won't go well with that. I will be replacing gaskets and seals so it will be fairly oil tight but want to keep that "old look". Does anyone know of a clear coat product that will stand up to engine heat?

Clearcoat? You got to be kidding. If you are trying to avoid the look of a job well done, just clean the engine and leave it at that.
The old engine block will likely be totally impregnated with oil, this should prevent any harmful rusting.
Your time and money may be better spent on replacing suspension bushings so the truck will drive straight.
In the end, you will do what you think looks just right. MY Dad used to say, "If we all liked the same thing, they would all be after your mother,"
There are confirmed stories of Old IHC in North America seasoning their engines blocks by allowing them to rust. BMW, in Germany did the same thing with buy-back used 1.5 liter engines. These 1.5 liter blocks were strong enough to resist damage from extreme turbo over boost. These engines were able to make 1500 horse power and last a grueling race.
My wife drove a 1971 2002. I modified the engine for her car and it produced a reliable 250hp. Because of instant throttle response, I installed a governor to restrict the rpm to 6000. The person who bought the BMW, destroyed the engine at nearly 10,000 rpm after he removed the governor. The block was punched out at any place broken connecting rods could reach.
https://youtu.be/_U5M6eIQpZk
https://youtu.be/SrDk9RzFw6s

BTW. You do not need a high temperature paint for an engine, unless you plan to operate the engine without coolant.
The running temperature should not exceed the temperature of boiling water at 212 degrees F. Probably, the operating temperature will be more likely 185 - 190 degrees Fahrenheit. Remember, a properly operating thermostat limits the low operating temperature, not the highest temperature. If your engine runs hotter than the thermostat numbers, the radiator or timing may need attention.

Nikki, as always a lot of good input by you! I liked the video you posted about the BMW racing motors including the interesting way they "seasoned" the block. I'll probably skip that step. Also good point about the paint not needing to be hi temp, I suppose only the exhaust manifold would need that. Tomorrow I'll be doing more cleaning on the engine it will give me some time to think about what I want to do for a finish on it.

I will be taking the exhaust manifold and the turbo hot side off my Cummins 4bta. The pieces will get a good glass beading followed by a ceramic coating inside and outside. One of the thoughts on glass beading and shot beading is these processes release stress in old castiron.
I like ceramic coating for improved performance, heat retention and improved appearance.
I am not telling anyone what to do with their stuff. You will figure out what works for your project.

Speaking of season blocks, a lot of family and friends worked at Cummins (my grandfather retired from there) and they also seasoned their blocks (at that time anyhow). I know GM and others used shot peening to strengthen engine components when they stopped forging them. Hadn't heard that with glass beading but I suppose its a possibility.