The Heavy Tank T101 was an American heavy tank project starting in April 1957 to counter the threat of new Soviet armored vehicles. The M46 Patton was not considered heavily enough armed or armored to counter the T-54/55. Though the T101 never saw service
Development
The T101 was based on a lengthened version of the T29 Heavy Tank and featured heavier armor, an upgraded Continental twin-turbo gasoline engine providing about 1100 bhp gross, 1000 bhp net, more comfortable positions for the crew, and a massive new turret incorporating a high-velocity L11A5 120mm gun.
References
T101 Wikipedia(Text) CC BY-SA