Atlas V https://en.wikipedia.org/wiki/Atlas_V https://en.wikipedia.org/wiki/Atlas_V has a first stage powered by the Russian RD-180 engine https://en.wikiped

Atlas V https://en.wikipedia.org/wiki/Atlas_V https://en.wikipedia.org/wiki/Atlas_V has a first stage powered by the Russian RD-180 engine https://en.wikipedia.org/wiki/RD-180 https://en.wikipedia.org/wiki/RD-180 and a Centaur upper stage powered by RL10 engines https://en.wikipedia.org/wiki/RL10 https://en.wikipedia.org/wiki/RL10 Vulcan Centaur https://en.wikipedia.org/wiki/Vulcan_Centaur https://en.wikipedia.org/wiki/Vulcan_Centaur has a first stage powered by Blue Origin's BE-4 engines https://en.wikipedia.org/wiki/BE-4 https://en.wikipedia.org/wiki/BE-4 and a second stage known as Centaur V. It's an upgraded version of the Centaur, also powered by RL10 engines https://en.wikipedia.org/wiki/Centaur_(rocket_stage)#Centaur_V https://en.wikipedia.org/wiki/Centaur_(rocket_stage)#Centaur... Vulcan has only flown once, in part because of slow delivery of BE-4 engines, which to date have not powered any other launcher (though they are meant to eventually power New Glenn). So I don't know what you mean by "Vulcan Centaur engines replacing the Russian RD-180".