As engineering design and development contracts await in the field with BAE Systems and SAIC, the U.S. Marine Corps has set a hard cap on upgrades to its fleet of AAV7A1 amphibious assault vehicles (AAVs).

The two engineering companies must keep the “survivability and capability” upgrades below $1.65 million per vehicle, according to DefenseNews.com. The pending contract relates to four battalions worth of Marine AAV7A1 AAVs, which currently stands at 392 vehicles.

While plans to ultimately replace the increasingly long-in-the-tooth AAV — which entered service in 1972 — are still a work in progress, the Corps has concluded that its most critical need is to improve protection of the Marines inside the vehicle while they’re in the water, and when the vehicle rumbles ashore.

A decision on the official contract to revamp the four battalions of AAV7A1s is expected to be made in February of 2015.