The Gate Of Good Fortune - Chapter 980

The empire has turned into the land of the undead due to a spell gone wrong. God summoned heroes from countless worlds to purify the empire and plant new hope. Lee Shin Woo, an ordinary earthling, was also summoned. As an undead, that is.

A scientific genius named Thomas Harrier was transmigrated to an imperial prince body after a car accident that took his life. He found out that he is in a world similar to our own with a timeline akin to early twentieth century. The body that he is occupying was the imperial prince of a failing empire who suddenly rose to power after a successful assassination attempt of his father. Unaware that the attack is just the beginning of what is to come. He faces many challenges throughout. Will Thomas Harrier be able to live his second life in peace while running an empire and getting it back to its former glory? Or will he succumb into a conspiracy lurking within the country's borders?

Expect some:

Cold war era techs.

Super battleship with advanced electronics, propulsion, and fire control systems?
Helicopters?
Missiles?
Modern medicines and equipment?
AC-130?
A nuke?
Challenger or Abrams or Leopard?
F-4 Phantom or MIG-21?
Colored TV's.

Everything!!!

PS. Cover not mine, I just found it on google.

Trying to drown her sorrow with alcohol after her boyfriend hooked up with her sister, Ning Qing ran into the rich and powerful Lu Shaoming in a bar. “I need a wife,” Lu said, and the two got their marriage license.

Soon, she who became a pop star won many pretty boys’ hearts. Singlehandedly, he got rid of all her potential flings and acted innocent. Ning Qing bristled, “Lu Shaoming, what happened to staying out of each other’s private life which we talked about?” Turning the light out, he came over her and whispered, “Now our priority is to make a baby.”

A small immortal clan, with the efforts of the ancestors of the past dynasties, slowly developed into an immortal clan. This is the history of the development and growth of a small family. During this period, there were ups and downs, and there were also struggles for power and profit.

- Description from novelbuddy