The Douglas DC-8 Super 70 Series was an exception. The DC-8-71, DC-8-72 and DC-8-73 were straightforward conversions of the -61, -62 and -63 primarily involving replacement of the JT3D engines with more fuel-efficient 22,000 lb (98.5 kN)
CFM56-2 high-bypass turbofans with new nacelles and pylons. A total of 110 60-Series DC-8s were converted by the time the program ended in 1988.