I feel there will always be a Sino-Soviet split at some point, but a delay is likely the case here. It would do wonders to the Chinese economy. (OTL it stopped the bulk of China's trade as well as cutting them off from Soviet aid.) So ALT China would be much further ahead for a while scientifically and its industry would be greatly improved as well. Best come to best you avoid Cultural Revolution. I say again, you may avoid the never ending nightmare that was OTL 1960s China. (Something that scared Brezhnev and Kim Il-sung to death.)
Both the USSR and PRC would agree on suppressing the Khmer Rouge before they get fairly started.
I agree that this would be good for the Chinese economy. It may not avoid the Cultural Revolution, depends how the broader context evolves.
However, I think there's a slim chance of avoiding the Sino-Soviet split.
Especially if Khrushchev isn't the leader of the Soviet Union and even better if Mao isn't the leader of China. Relations might be tetchy, as Soviet arrogance and Chinese pride grated against each-other like tectonic plates, but I can imagine personalities and scenarios where a full rupture would be avoided due to a clash being a little more vexing that not getting on with the abrasive neighbour.
And I think eventually (in the 70s, perhaps, though potentially earlier) the Soviets would acclimate to treating China as a real equal.
Interestingly, better relations with China would free the Soviets to take a harder line in Eastern Europe and with the West.
This is assuming China can still develop it's industry as effectively if it's tied into the Soviet economic Bloc. The presence of large Russian imports and continued protection relations is going to take alot of drive out of the economic and political motivations for "self stregthening", since there's no need to become self relient for security or stability of supplies sake. We could just as easily see a China go into an import trap/ fall into "Third World is" as Maoist theory suggested
I am doubtful that this would happen to China. For one thing, they have a more solid resource base than any 3rd world state. Also, considering how cumbersome trade was between Soviet-style states, importing too much from the Soviet Union would just be a giant bother. Further, China had already experienced a humiliating 19th and early 20th Century where they didn't have first rate industries - national pride would add to Marxist theory and push China's leadership to seek a broad and powerful industrial base for their country.
Could have China industrializes along the lines of Chen Yun's proposed economic plans, which calls for continued emphasis on light manufacturing. This means that there is an acute demand for capital goods in China, which really only the Soviet Union will be willing to provide in the 1960s. China therefore cannot afford to piss off the Soviet Union. (Not Third World.)
So I've only read a little about Chen Yun - my impression though is that he was pro-heavy industry, but thought China had overdone it and needed a healthy balance between heavy industry, light industry and agriculture. That doesn't sound to me like a guy who'd make China completely dependent on Soviet heavy industry.
fasquardon