At the end of 1942 the Soviets sent a T-34 and a KV-1
to the United States for familiarization with their designs.
I have never read the Report from the Aberdeen proving grounds that did the testing, but I have read a Russian report to higher authority summarizing the American report.
One of the more interesting comments in this summary was a atatement in the American report that “the designer of the air cleaners (on the T-34)should be tried for treason.” Overall the Aberdeen people were very impressed with the Soviet designs, but found Soviet engines and transmissions to be rather poorly manufactured when compared to American machinery.
As you may know, engines for Soviet tanks was basically from tractors. There is a true story about t-55/62 tanks that was taken by Israelis after Yom Kippur war(1973).In mid-70’s Israel asked Romania to sell Soviet tractors K-700/750.Romanians was very happy to get hard currency and sold few hundred of them. Soviets started to analyze the situation and tried to figure out why Israelis needed their tractors. When conclusion was reached it was too late. There was a need for engines/parts for T models and they are the same.