Ford’s double overhead-cam Indy V8 not only looked fabulous, it was a winner too, with seven Indy 500 victories. Here are a few of its secrets.

Unlike many exotic racing engines campaigned by the major auto manufacturers, the Ford Indy V8 was produced in-house by Ford personnel, which is unusual in itself. More often, specialist companies such as Cosworth and Ilmor do the work. Shown above are Gus Scussel and Joe Miller, Ford’s two lead engineers on the program. As radical-looking as the Ford DOHC Indy V8 was, it was actually based on a standard Ford production engine—the 221 CID Fairlane V8 introduced in 1962.

For the ’63 Indianapolis 500, Ford developed a 255 cubic-inch version of the Fairlane V8 with an aluminum block and heads and other refinements. Though it retained the production pushrod valve layout, this V8 was surprisingly successful, nearly winning the race in a Lotus-Ford driven by Jim Clark. Encouraged by the result, Ford pulled out all the stops for ’64 and designed a double-overhead-cam version with four valves per cylinder, but it still used the basic Fairlane V8 architecture and key dimensions.

Ford tested several more conventional DOHC layouts before settling upon the radical configuration above, which was designated  the Phase III engine. The standard camshaft locations are reversed: Here, the exhaust cam is on top and the intake cam is below. The exhaust ports then exit at the top of the engine, while the intake ports are routed between the camshaft towers. Among other things, this setup created the Indy V8’s unusual appearance—like nothing seen at the Indianapolis Motor Speedway before or since.

Above is a closer look at the distinctive cylinder head design, which permitted an intake port that was not only huge, but nearly a straight shot to the intake valve. The approach was based on elaborate calculations to determine optimal aiflow volume and velocity for the four valves per cylinder, 1.46-in intake and 1.36-inch exhaust, with.440-in maximum valve lift. (For more, see Stossel’s SAE paper no. 640252.) Under each of the eight individual throttle blades was a nozzle for the modified Hilborn constant-flow fuel injection.

In other ways, the design followed conventional racing engine practice of the time, with wide valve angles, direct-acting bucket-type cam followers, and pentroof combustion chambers. However, Ford engineers discovered that the chamber design defied conventional machine tools, so an electrical discharge machining  (EDM) process was used. Conventional head gaskets wouldn’t do, either, so laminated copper rings sealed the cylinder bores.

A set of 13 straight-cut steel spur gears at the front of the engine drove the oil and coolant pumps, camshafts, and accessories, with the Hilborn fuel pump and Ford breakerless distributor driven from the exhaust cams. Another benefit of the unusual cylinder head layout was that it enabled the effective (and fabulous-looking) 180-degree headers, the signature visual feature of the Indy V8.

Running on 103-octane gasoline, the 255 CID V8 easily met its performance targets: 425 hp at 8,000 rpm and 295 lb-ft at 6400 rpm. Ford had chosen gasoline over methanol as the best compromise between power and fuel consumption, but after the tragic 1964 fire at Indy that took the lives of Dave MacDonald and Eddie Sachs, gasoline was prohibited. A Ford didn’t win in ’64, but they dominated the event for the next three years, ’65 through ’67.

By 1968, however, the Offenhauser-powered teams had mastered the turbocharger and they were back in contention, winning the 500 that year. The Ford contingent quickly answered back with a turbocharged version of the Indy V8 destroked to 159 CID, winning three straight Indy 500s in ’69-’71. When Ford exited from racing after 1970, A.J. Foyt Racing took over the Indy V8 program, often running cam covers that spelled out F-O-Y-T instead of F-O-R-D.

While the turbocharged Offys dominated much of the ’70s with their uncanny ability to gobble up boost, the Ford/Foyt V8 had one final moment of glory at the Speedway in ’77. There, Foyt scored his fourth Indy 500 win with a Coyote Ford—shown below with its Indy V8 buried in turbocharger plumbing.

Foyt would return with another Ford V8 in 1979, but this was a Cosworth DFV/DFX, not the original Indy V8, and the Cosworth with its next-genreration technology would rule at Indy for nearly a decade. While they are sometimes confused, the Cosworth and the Indy V8 are two totally different engines, sharing nothing in common apart from their Ford badges.