Isreal was using WWII Sherman tanks until the 1980s! They were highly modified with up to a 105mm main gun and a diesel engine. Israel's Shermans were used with success in the invasion of the Sinai in 1956 and the Six-Day War. All the Shermans were taken out of Israeli service in the late 1980s and sold to Chile, who used them all the way up until 1999! That's an outstanding and long service record.
Description: Sherman M-51 (Isherman) in Yad la-Shiryon Museum, Israel. 2005.
Source: Wikipedia User:Bukvoed.