After a disastrous 1964 racing season, Ford turned the GT40 project over to Carroll Shelby and Shelby American. Ford's team had proven the GT40's could compete with the best of Europe but 10 DNFs out of 10 starts called for an experienced hand. The Shelby American team had been winning a lot of races with the Cobras. Even though the Cobras were Ford powered, they weren't Fords. Cobras were a hybrid car at best. And Lee Ioccoca at Ford Motor Company wanted Ford to have racing victories. Ford asked Shelby to pull the factory support of the Cobras and race the GT40's instead. Carroll Shelby had no trouble understanding the request and closed down the official Cobra racing efforts, devoting all Shelby American's efforts to win with the GT40's.
During the 1964 season, GT40's couldn't stay in the races. Engines would break. Transmissions burnt up. The first thing the Shelby team did was pull the exotic, troublesome engines and replaced them with the tried and true 380 HP 289 CID. The Shelby team also reconstructed the unreliable ZF 5 speed transaxle (21 changes in all).
Shelby's GT40 team won the first two races of the 1965 season at Daytona and Sebring. The next three races, Monza, Targa and Nurburging were disappointing at best. Bob Bondurant was driving a GT40 with John Whitmore at Targa. The race was only 10 laps long but each lap was 45 miles. They drove it to as high as third place prior to some mechanical problems and a crash. . The car had a continuous oil leak during practice. They thought was it fixed. When Bondurant pitted, half of the oil was laying on the floor. During Whitmore's turn at the steering wheel the left front wheel came off. A local Silician found the knockoff that secured the wheel planning to keep it as a souvenir. Whitmore talked him into giving it back and put the wheel on the GT40. Back in the pits, Bondurant took over. On the track, Bob hit some loose gravel, went off the road and hit one of the kilometer markers buried along the track. It smashed the front of the car, put the car up on two wheels almost flipping the car over. It landed on all four wheels. Bondurant got out the car and started walking back to Cerda. Along the way he came across a bar in a hotel and that's where Carroll Smith later found him.
But while the GT40's were being prepped, Ferrari and the competition were also gearing up for the upcoming confrontation. More horsepower was needed for the GT40 so Shelby's team modified a Mk I to accommodate the 7 liter 427 CID. The small block would power the GT40's to 200 MPH. But the 500 HP 427 topped 210 mph the first time out with Ken Miles at the wheel. Called Mk IIs, the big block GT40's were plagued with aerodynamics & high speed handling problems.
At LeMans in `65 the GT40's ran off with the race only to succumb one at a time to problems with the new Kar Kraft 5 speed transaxles. The small block GT40's had gearbox and cylinder head problems. All dropped out of the race. Ford once again pulled out of European racing for the rest of the `65 season.
Ford regrouped by the '66 racing season and was even more determined to win in Europe. The big block was definitely the way to do it. A decision was made to enter three teams, under the assumption that three cars were the most any one team could handle successfully. In addition to Shelby American, Ford enlisted the help of big block stock car winners, Holman & Moody, and Alan Mann. Ford's Kar Kraft tested all the 427 engines and drive trains for reliability.
A Mk II GT40 was converted to an open roadster. It was given to Bruce McLaren for further development. The 427 powered car was entered in the `66 Sebring race and Ken Miles drove it to first place. An interesting story is told about Dan Gurney in that race. Gurney had qualified for pole position in a Mk II. At the start of the race, Gurney was the first one to sprint to his car, only to find his GT40 wouldn't start. The rest of the 64 cars had gotten away and were out of sight before he got the big block started. By lap 10, Gurney had passed 54 cars to take 10th place. By the first hour he had set a new lap record and moved past Ken Miles to lead the race. Gurney & co-driver Grant held 1st place until the very last lap. Only 1/4 mile from the finish the GT40 quit! Gurney got out and pushed the car across the line only to be disqualified. If he had stayed in the car, he would've gotten 2nd.
Ford sponsored eight GT40's in the 1966 LeMans. Mann had -2, Shelby-3 and Holman & Moody-3. Also in the race were 5 privately owned GT40's. By the end of the race, only three were still running. But two of Shelby's finished 1st & 2nd, and Holman & Moody's sole surviving GT40 took 3rd. After three long frustrating years, Ford had finally won at LeMans. Ford also won the `66 World Prototype Trophy and World's Sports Car Championship. The Europeans called it a fluke. Ford was determined to prove it wasn't.
At the '66 LeMans a new GT40 body was tested. Dubbed the "bread wagon" because the rear didn't slop towards the back of the car, the body was constructed of an aluminum honeycomb glued together. The Mk IV set the fastest lap ending all doubts. Four more Mk IVs were built by Kar Kraft for the '67 LeMans. This was the first GT40 body to be built entirely in the US. During testing at Riverside, Ken Miles was killed when his Mk IV crashed for no reason, costing Shelby another old friend and his top development driver. Miles death slowed the Mk IV project until the Mk IIs started having transaxles problems at the '67 Daytona race. Once again Shelby's team was called in the get the Mk IVs ready for LeMans. In less than a month, Shelby's team had the Mk IV running faster the Mk IIs. One MK IV was entered at Sebring and it came in first. By LeMans, seven Mk IVs were ready. Shelby was given 2 Mk IVs & 1 Mk II. Holman & Moody had the remaining 2 Mk IVs and 2 Mk IIs. First & 4th place went to Shelby's GT40's.
Ford had taken the '67 LeMans, winning the race two years in a row. The other GT40's didn't finish. Only one was due to mechanical problems, the others were all out due to accidents. Dan Gurney and AJ Foyt drove Shelby's winning GT40 at an average speed of 135.48 MPH for the 24 hours covering 3,249.6 miles, breaking the old record by the greatest margin ever! That record wasn't broken until 1971. After the race, the 427 was dynoed at 499 HP, four more than it had at the beginning of the race.
After the `67 LeMans race the International racing rules committee banned engines larger than 5 litres. The LeMans officials had even tried to stop the GT40's during the race when it was obvious no other car could keep up with the Fords. Ford had proven its point, and withdrew from active racing after that. Ford won the '67 World Sports Car Championship, for the second year. Shelby also quit international racing.
That wasn't the end to the story of the GT40's. John Wyer, supplier of the original GT40 bodies, fielded a team of 289 powered Mk Is backed by Gulf Oil, called Mirages. Wyer's team won all but one of the International Championship races in `68, winning the World Manufacturers Championship. The Europeans were beside themselves. Ford's GT40 dominated racing in '68 with a body that was designed 4 years before!
The next year, in '69, Ferrari and Porsche had new 12 cylinder engines with the same capacity of the V-8 289s and new state of the art bodies. A Wyer GT40 won the 12 hours of Sebring. At LeMans a total of 20 Porsches & Ferraris were entered against two GT40's and Wyer's' one Gulf-Ford GT40. Wyer's' Mk I, chassis number 1075, won giving Ford four straight years of victory at LeMans. That was also the same car that had won the '68 LeMans, something that has not since been done. The Ford GT40's were still the best racing cars in the world.
To read more about the Shelby American efforts with the GT40 and see some great pictures pick up a copy of David Friedman's GT40 book from Motorbooks.