"J" Car to Mark IV: A Rough Road to Victory.

[Cal Metal]

This excerpt is taken from Peter Lyon's piece published in AW in 1987 in the "Escape Road" section. A good piece that is more indepth than most one page articles.

"........What would become the Mark IV GT-40 was Ford's third bid to solve the Le Mans problem. It, too, was initiated by Lunn, who to differentiate it from the older tech GT-40 called it the "J" car after FIA appendix J racing regulations. His first proposal for the J-Model was presented in late June of '65 and the first example ran on the first of March 1966. But it never did become raceworthy that year. As with the original GT-40 and the bigger engined variant, the MK II, Ford apparently first had to prove all over again that design is one thing, development quite another.

"..........The J-car was, after all, a radical machine in most respects. The only familiar item at first was the thumping great "side oiler" 427, the 500 HP iron block V8 from the Mark II. An automatic transmission was part of the original plan. So was its wedged shaped body, one of the earliest attempts at aeordynamic down force. What the car is most remembered for, however, was its lightweight chassis, racing's first significant application of aluminum honeycomb.

"...........None of these innovations was without its problems. Two different automatic transmissions designs turned out to absorb a lot of power for no effective gain in operation. The wedge body proved too draggy for Le Mans. And after one J-Car crashed in testing, breaking in half and ejecting Ken Miles to his death, weight was added to the honeycomb tubs of subsequent ones.

".........That there were subsequent J-Cars was itself something of an anomaly, for many had low confidence in the concept. Ford Initially planned its l967 endurance program around the now faithful MK II. But at the first race of the new year, in February at Daytona, the MK IIs went out with identical transmission failure; in any case, Ferrari's new P4 had shown unexpected speed. In an atmosphere of near-desperation the J-Car was put through intensive development. The most prominent change was aeordynamic. Completely new nose and tail sections increased striaghtaway speeds by up to 10 mph, so for the first time the J-Car showed more top end than a MK II (about 215 mph vs 211 mph). The car was less stable than before, but the drivers said they could race it. To differentiate it from the despised J-Car, someone had hand painted a new designation, "MK IV" on the new nose. On April 1 at Sebring, driven by Andretti and McLaren, in a stirring battle it defeated the 2F Chaparrak to winits first race.

"......."It was one of those death defying programs, you know?" recalls Andretti of the J-Car/Mark IV transformation "(Fabricator) Phil Remington just flat went to work, chop-chop-chop, HE DID IT. He just kind of eyeballed a shape. We took it to Kingman, Arizona, just before Sebring to test it against a Mk II. The Mark IV was immediately head and shoulders above the MK II, certainly in the aerodynamics. More slippery. The rest of it , the construction of the chassis and everything, was stiffer It felt more responsive. It felt more like a thoroughtbred. It was definitely a car to choose from that point on. I didn't want to drive, for any reason, a Mark II after that", said Andretti..........."