Only NK-33 modified into AJ-26 used on Antares rockets is manufactured in early 1970-s. RD-180 was designed in 1990-s, about the same time as RS-68, the engine

Only NK-33 modified into AJ-26 used on Antares rockets is manufactured in early 1970-s. RD-180 was designed in 1990-s, about the same time as RS-68, the engine from Delta-IV first stage.