$208 million compared to $221 million for Chrysler. In July 1976, Lt. Colonel George Mohrmann prepared a stack of letters informing Congress of the decision to move ahead with the GM design. All that was required was the final sign-off by the Secretary of Defense, Donald Rumsfeld. Chrysler is chosen On 20 July 1976, United States Secretary of the Army Martin Hoffman and a group of generals visited Deputy Defense Secretary Bill Clements and Director of Defense Research and Engineering Malcolm Currie on their decision. They were surprised when Clements and Currie criticized their decision and demanded the turbine be selected. Donald Rumsfeld heard arguments from both in the afternoon and asked for twenty-four hours to review the issues. The Army team spent the night writing briefs and presented them to Rumsfeld the next morning, who then announced a four-month delay. Within days, GM was asked to present a new design with a turbine engine. According to Assistant Secretary for Research and Development Ed Miller, "It became increasingly clear that the only solution which would be acceptable to Clements and Currie was the turbine... It was a political decision that was reached, and for all intents and purposes that decision gave the award to Chrysler since they were the only contractor with a gas turbine." However, the Chrysler design had the advantage that the entire power pack had room to be replaced by any number of engine designs, including a Diesel if needed. The turbine engine does not appear to be the only reason for this decision. Chrysler was the only company that appeared to be seriously interested in tank development; the M60 had been lucrative for the company and relied on that program for much of its profit. In contrast, GM made only about 1% of its income from military sales, compared to 5% for Chrysler, and only submitted their bid after a "special plea" from the Pentagon. On 12 November 1976, the Defense Department awarded a $20 billion development contract to Chrysler. Production starts In January 1978, a program was initiated to develop an enhanced version of the 105mm gun, the M68A1 as a possible alternate weapon for the M1 Abrams. The new XM24/L55 gun barrel was 18 inches (45.72 cm) longer in comparison to the XM24/L52 barrel used on the M60 tanks. It has a higher chamber pressure, reinforced breech and a higher muzzle velocity. Low rate