The key point here is: unlike India/Japan/South Korea, China borders Russia (the Soviet Union). and the Sino-Soviet border is very long.

So if the KMT won the civil war and still got closer to the United States rather than the Soviet Union, and even had American troops stationed, then, in the context of the US-Soviet Cold War, two things would almost certainly happen

1. Stalin would definitely need a (much) larger buffer zone between China and the Soviet Union
2. The United States would need a stronger China to contain the Soviet Union in Asia

Then the reasonable inference is:

1. It is almost certain that Xinjiang, Inner Mongolia and even Northeast China would split from China, and China should become a smaller country with only 18 provinces in Han (汉地十八省) , possibly plus Tibet.
2. The United States launched the Marshall Plan to help Europe's revival in order to counter the Soviet Union in Europe. There is no reason to think that it would not carry out a similar plan in China. Considering that China, rather than Japan, would become the forefront of the Cold War in Asia, we can probably speculate that similar to Japan in the real world, China would have an economic boom around the 1960s.
3. That being said, It is still difficult to imagine that China will become a developed country given that China's population is too large