Was COMECON involved in economic imperialism and if so, to what extent?

This is unfortunately the only source I could find which describes COMECON's imperialist tendencies in great detail. The article was written in Albania in 1981, so one should take it with a grain of salt as Albania was not in the Soviet camp but the Chinese, and it was not so long ago that China and the USSR experienced a massive deterioration of relations. The article also does not reference many sources but I think that Albania, being aligned to the Communists, would have a better perspective of reality east of the Iron Curtain than anyone in the west.

I have extracted select statements of interest below. The article states that the intention originally was probably to control the satellite states but over time evolved into corruption on a state scale. For example, as was the case in Czechoslovakia and Hungary:

For example, through “reconstructions”, such big trusts as SKODA, CKD, TESLA, etc of Czechoslovakia, renowned for the production of heavy machinery, automobiles, electric equipment, etc have been forced to work mainly to meet the demands of the market of the Russian metropolis. Likewise, allegedly in the context of “specialization”, Hungary has been compelled to gear its “Red Star” plant in Budapest mainly to the production of tractor brakes, although it had long been producing complete tractors. Now the needs of Hungarian agriculture for tractors are fulfilled with imports from the Soviet Union.

The aim of the Soviet revisionists to impose a course of one-sided development on the Comecon countries, is also apparent from their efforts to hinder the full-cycle development of the new branches which these countries are allowed to establish. A typical instance of this is the prohibition of the development of the aluminium industry in Hungary, although it is rich in bauxite. Under the plans of “cooperation and specializations which the Soviet revisionists have imposed on Comecon, this industry must be developed in the Soviet Union which secures the raw materials from Hungary, while the latter must meet its needs for aluminium products by importing them from the Soviet Union!

The side effect, of course, was that these satellite states became heavily indebted to the USSR. Bulgaria for example had a -2 billion ruble account to the USSR by the time of the article's writing (I think 1981).

COMECON also regularly pushed expenses off the USSR's accounts to their satellites:

During the current [not clear which the author is referring to, possibly 10th] five-year plan, for example, according to figures published by the Soviet revisionists themselves, on the basis of “coordination” within Comecon. or bilateral agreements, more than 1,000 complete sets of equipment for industrial projects, including equipment for six urea plants with an annual capacity of 6 million tons, and 21 sulphuric acid plants with a total capacity of 10 million tons a year, 46 plants for the food processing industry, etc, etc, will be delivered to the Soviet Union. According to Comecon decisions, these plants and combines become the property of the country in which they are built...

I.e. equipment will be made in the satellites, shipped over to the USSR and become the property of the USSR without any chance to negotiate licenses or leases.

Lastly, it seems that COMECON was involved in outright robbery through price gouging of fellow Warsaw Pact states:

For example, the prices at which the Soviet revisionists sell iron ore to the [sic] countries of Eastern Europe are 10-15 per cent higher than world market prices, those for Soviet machinery are 1.4 to 2.1 times higher, etc. However, the machinery imported from the German Democratic Republic is priced by the Soviet revisionists 25-30 per cent below world market prices. This non-equivalent exchange is even more apparent in the agricultural products which the Russian metropolis imports from its Comecon vassals. As a result of this unscrupulous robbery, during the 8th Five-year Plan alone, the Soviet bourgeoisie secured a supplementary profit of 3.5 billion rubles.

The article concludes that the effects on the satellite's economies were quite devastating:

Such a predatory practice has grave consequences for the economies and finances of the member countries of the Comecon. Solely because of the rise in the price of Soviet oil in 1975, which of course, was not accompanied by increased prices for the commodities the Soviet revisionists buy from the other revisionist countries, the Comecon member countries had to pay the social-imperialist Soviet Union an additional one billion rubles.

http://www.marxists.org/history/erol/albania/al-comecon-81.pdf

• Yes, SU did its best to make sure that its satellites were controlled as tightly as possible.
• No, SU did not stunt their growth intentionally, but it might have done it as a side effect of the general economic policy (priority was given to heavy industry which could be mobilized for war production)

SU wanted to have as much leverage over the satellites to make them productive elements of the common economic system. The Soviet leadership understood that military power was determined by the industrial power, and expanded the latter as long as it could control it and use it for its own war machine.

E.g., Ioffe writes writes about SU forcing the Czechoslovaks to build a reactor which would require enriched uranium (which would require soviet supplies) instead of natural uranium (which Czechoslovakia could produce on its own).

There are many more examples sprinkled over various memoirs...

PS. The old Soviet joke:

• Q: Does SU rob (as the satellites claim) or feed (as the Russians claim) its satellites?
• A: SU robs its satellites naked, to the degree that it has to feed them so that they do not starve to death.

(this is actually the correct description of the Soviet state's relationship with all its subjects, whether individual citizens or regions; moreover, it describes well the relationship of masters with their slaves throughout history)

PPS. This is a very touchy issue for the resurgent Russian imperialism, so be careful about what you believe.