The M8 Greyhound's excellent road mobility made it a great supportive element in the advancing American and British armored columns.

[citation needed] The M8 was not designed for offensive combat, and its firepower was adequate only against similar lightly armored enemy vehicles and infantry.

Conversely, the performance of the M8 on hard surfaces was exceptional, with the vehicle having a long range and able to consistently maintain its top speed of 55 mph.

The M8's armor was thin, but it provided protection for the crew from small-arms fire and shrapnel, enough so that the vehicle could carry out its main mission of reconnaissance.

The M8 was initially fitted without any kind of anti-aircraft defense; as a stopgap solution a .50 caliber Browning M2HB machine gun on a ring mount was retrofitted to nearly all vehicles already in service.

With a 54 US gal (200 L) fuel tank, it could manage a road range of 200–400 miles (320–640 km) The Hercules JXD ran more quietly than other engines of comparable power, which helped the M8 maintain an element of surprise and reduce the chance of being heard by the enemy.

Off-road mobility, especially on soft ground like mud or snow, was poor;[12] in the mountainous terrain of Italy and in the Northwest European winter, the M8 was more or less restricted to roads, which greatly reduced its value as a reconnaissance vehicle.

[13] Although the T28 was standardized as the M28 and marked for production by Ford, the new armored car program was shelved and then permanently cancelled due to the end of the war, as impetus and funding for new military development projects had plummeted.

[13] The fleet of M8 and M20 armored cars already available was then considered more than adequate for the postwar US Army, which was demobilizing thousands of personnel and already had large stockpiles of equipment surplus to its requirements.

[13] After the war, many of the US Army's M8 and M20 armored cars were marked off as surplus and donated or sold to various countries, especially under the Foreign Military Assistance Program (MAP).

[1][page needed] The others were utilized by the Military Police Corps, which deployed them during the Korean War for guarding static installations and escorting prisoners.

[1][page needed] When the Army National Guard retired its own armored cars a few years later, an undisclosed number were purchased by domestic police departments and modified for riot control purposes.

[1][page needed] France was the largest postwar operator of the M8/M20 series after the United States, having received hundreds of the vehicles as American aid between 1945 and 1954.

[1][page needed] These remained in service in Indochina until the end of the war, when they were donated to the Army of the Republic of Vietnam (ARVN).

[1][page needed] ARVN M8s and M20s saw considerable action during the Vietnam War; however, by 1962 the US noted the attrition rate of the fleet was becoming high due to age.

[13] This resulted in a proposal to fund the design and production of a new purpose-built armored car for the South Vietnamese government: the Cadillac Gage Commando.

[13] A small number of the older armored cars were still held by the ARVN reserves as late as 1975; these were inherited by the People's Army of Vietnam after the war.

[17] The continued proliferation of M8s and M20s during the late 1960s and the 1970s resulted in American and French defense contractors offering several commercial upgrade kits to extend their service life.

At least ten countries, Cameroon, Cyprus, Ethiopia, El Salvador, Guatemala, Haiti, Jamaica, Morocco, Venezuela, and Zaire, modernized their M8/M20 fleets with diesel engines and new transmissions during this time.

[1][page needed] The National Army of Colombia also invested heavily in upgrading the M8's turret armament, having it replaced by a single .50 caliber machine gun and a launcher for BGM-71 TOW anti-tank missiles.

[18][19][20] This project spawned a series of indigenous prototypes, including a bizarre four-wheeled variant of the M8 chassis known as the VBB, and another more conventional six-wheeled design known as the VBR-2.