From the article:
Israel attempted to acquire Centurion tanks for several years from Britain, but was rebuffed until after the Suez Crisis of 1956. In 1959 a clandestine army delegation was sent to Britain to begin training and familiarization with the Centurion tank. As the agreement was secret, the code name Sho't (Scourge or Whip) was used to refer to the Centurion in Israeli service. Israel initially received roughly 20 used Mark 5 tanks, but later began to purchase new Mark 8 tanks. By the time of the 1967 conflict, Israel had nearly 300 Centurions in service. All but 12 used around Jerusalem had been upgraded with the new British 105mm L7 gun.
The Centurion originally had a poor reputation with the Israeli Defence Force, being thought unreliable and inaccurate. This turned out to be a result of the Israeli's extremely ‘rough and ready' approach to maintenance and gun calibration. After an embarrassing incident during the Water War in which they failed to hit anything in a day-long engagement with the Syrians, the Armoured Force dramatically improved their maintenance and gunnery practices. After that the Centurion became the preferred tank for its accurate gun and resilience when hit.
After the Six-Day War of 1967, the Israelis further upgraded their Sho't Centurions by replacing the Meteor petrol engine with an American Continental diesel engine, giving it more speed and a longer range