The six Jumo 004 engines of the EF-131 were replaced by two Mikulin AM-TKRD-01 axial flow turbojets, rated at 32.372 kN (7,280 lb) thrust, in large nacelles attached to the underside of the wing at the same position.
[1] The prototype was completed quickly and ready for flight tests by late September 1948 after being disassembled and transported to Tyoply Stan airfield on the outskirts of Moscow.
1886-696 called for development of 140 as a tactical reconnaissance aircraft powered by two Klimov VK-1 centrifugal flow turbo-jets.
During the design work for the '140-R' the deficiencies highlighted by flight testing of the '140' were addressed as well as the addition of wingtip-mounted fuel tanks and new nacelles for the VK-1 engines, and the fitting of DT-V1 and DT-N1 turrets, replacing those of the '140', armed with 2 × 23mm cannon each.
[1] The final variant of '140' was the '140-B/R', which was a reconnaissance bomber, powered by the same engines but with increased weight and reduced performance.