The H-1 upgrade program is the United States Marine Corps's program to develop the AH-1Z Viper and UH-1Y Venom military helicopters to replace its aging fleets of AH-1W SuperCobras and UH-1N Twin Hueys. The contract was awarded in 1996 to Bell Helicopter, the original manufacturer of both aircraft, to design the new airframes as modernized attack and utility helicopters with considerable design commonality, to reduce operating costs.

Bell Textron Inc. is an American aerospace manufacturer headquartered in Fort Worth, Texas. A subsidiary of Textron, Bell manufactures military rotorcraft at facilities in Fort Worth, and Amarillo, Texas, USA as well as commercial helicopters in Mirabel, Quebec, Canada.