Modernized Centurion tanks with 105 mm gun from 1963 and new powerpack of the Continental AVDS-1790-2A diesel engine mated to the Allison CD850-6 transmission. Entered service in 1970; by 1974, all Israeli Centurions were upgraded to Sho't Kal (Mk 13 armor) and had a pintle-mounted .50 cal HMG. Subvariants indicate upgrades received by Sho't Kal tanks during their operational life, including a new turret rotating mechanism, a new gun stabilizer, a new fire-control system and preparations for the installation of the Blazer ERA.