I know it may not be what your looking for but I think a lot of your answers will inevitably be in regards to rocketry.

On that front, the Soviets developed a number of advanced rocket engines, some of which are still some of the best in the world. The RD-170 for instance maintains the title as the most powerful rocket engine in the world. Most people believe this title goes to the American F-1 engine which was used for the Apollo program. However the F-1 is only the most powerful single cone engine, and comparatively the RD-170 outputs over 1,000,000 more Newtons of thrust.

Secondly the NK-33 rocket engine which was originally developed for the Soviet Moon program has the second highest thrust to weight ratio of of any rocket. Similarly, it also has a very high specific impulse. It's only other contender is the SpaceX Merlin 1-D which was developed very recently.