Shelby American worked with Ford to re-engineer the GT40 for the '66 season, replacing the 289 cubic inch (4.7 L) engine with Ford's larger, more powerful 427 cu. in. (7.0 L) engine. The Mk II GT40 achieved great success, with Shelby American's wins at Daytona, Sebring and Le Mans earning Ford the International Manufacturer's Championship in 1966. Shelby American cars finished first (Miles &amp; Ruby again) and second (Gurney &amp; Jerry Grant) at Daytona, first at Sebring (Miles &amp; Ruby), and first (McLaren &amp; Chris Amon) and second (Miles &amp; Denny Hulme) at Le Mans. Gurney and Grant would have finished second at Sebring except their car broke down on the last lap and Gurney pushed it across the finish line, automatically disqualifying them.