Do you plan to paint the truck, or leave it in its present condition, which btw looks awesome, unless there are things about the body unseen by the viewers that you want to fix? Something about seeing a classic in its natural weathered state vs. a pretty truck like mine! You can still use your truck as a truck! Show trucks are somewhat useless for work
I've still been thinking about your idling problem and having to have the choke on or partially on to keep it running? Unless you've remedied that issue. I had kind of the same problem on the original engine in my truck, it was a 230 or 250, but wouldn't idle unless I put my hand over the opening to act as a choke, then it would run. In my case it would up being the carburetor, but I had to eliminate the possibility of vacuum leaks around the intake manifold(it was loose somewhat). Using a can of carb cleaner and spraying to where the intake mating surface to the head can help identify leaks when the engine is running, as it will speed up in idle when carb cleaner is drawn in. However, spray carb cleaner can make its way to the inlet of the carb and give a "false positive", so you have to shield the spray from the carb. I had three extra carburetors, but each of them had issues. Of course that engine was pulled out and an sbc installed.
Another thought and just curious, have you performed a compression test on the engine? It's an easy test.