Just in the interest of historical accuracy, Jeep dropped the Gladiator title in 1971. Trucks built after that were simply a Jeep truck. They had weight class designations like J10, J20, etc, but there was no more Gladiator.
And I could be wrong on this since its been a while but as I recall the 327 Vigilante V8 was long gone by 1984, so if that's the case and based on the photos, I'd say that is probably a standard good ol' AMC 360.