The US Marines have had two programs to upgrade their nearly Vietnam era helicopters.

The upgrades are known as the UH-1Y and the AH-1Z.

In addition to changes to avionics, these also involve upgrades to the engines and rotor systems.

It now appears tatt the the final 40 deliveries will be completely new airframes, as opposed to rebuilds.

From a FMS (foreign military sales) perspective, this means that Bell will be able to sell new build AH-1 helicopters with 4 bladed rotors, and modern T700 engines.

This is good news for Bell, which makes the AH-1 Cobra, and bad news for Boeing, which makes the AH-64 Apache, which is much larger and much more expensive to purchase and operate.

Much of the utility in an attack helo is in its sensors and fire control systems, and the AH-1Z will be very close to the AH-64 in those capabilities, as well as in weapons load, though it will not carry the hideously expensive Longbow radar system.