In the mid-1970s, the M48 series Tank upgrade was developed to allow the vehicle to carry the heavier 105 mm gun. The original program designation was XM736. The designation was subsequently changed to M48A3E1 and was finally standardized as M48A5. As many components from the were utilized as possible. was issued a contract to convert 501 M48A3 tanks to the M48A5 standard and this was completed in December 1976. These early M48A5's were essentially M48A3 tanks with the 105mm gun added. They retained the M1 cupola armed with a .50 cal machine gun.
Based on Israeli experience in upgrading M48 series tanks, further changes were instituted during the conversion process. These changes began to be incorporated in August 1976. These included replacing the M1 cupola with a low-profile "Urdan" type cupola that mounted an machine gun for use by the tank commander. A second machine gun was mounted on the turret roof for use by the loader. Internal ammunition stowage for the 105mm main gun was also increased to 54 rounds. These tanks were initially given the designation M48A5API; but, after early conversions were brought up to the later standard, the API was removed and these tanks were known simply as M48A5.