• In the early 1930s, stock-block engines were still fairly viable at Indy, and Preston Tucker felt that in a modern, independently sprung chassis, one might have a chance to win the 500-mile race.
• Harry Miller didn't have much regard for the racing potential of any American stock engine, but he had a wealth of very advanced ideas on chassis design.
• Miller had Everett Stevenson sketch layouts of racing cars with both v-type and in-line engines. Common to all the proposals was a very low body profile, four-wheel independent suspension, and front-wheel drive.
• In the early 1930s, the Ford Motor Company was pushing a performance image for their line as hard as Depression conditions would permit, and its side-valve V-8 engine was one of the more likely hop-up prospects in the industry.  A few examples had already competed at the Indy Motor Speedway, though without any particular success.
• Tucker pitched the deal hard to Edsel Ford, who then pushed the right buttons and the deal was accepted in February 1935 by N.W. Ayer and Co., Ford's ad agency. 
• Miller and Tucker formed Miller-Tucker, Inc. to execute the contract with Ayer.
• Harry Miller called Everett Stevenson to Detroit in early March, and told him to lose no time in starting on working drawings for the Miller-Ford racing cars, as there was less than three months in which to build the staggering total of ten complete cars.
• Miller and Tucker borrowed a lot of equipment from Ford to stock their race car plant in Detroit, and by the time the cars were actually racing, every man of value at Ford's Engineering Department in Dearborn was working frantically on the project.  All but the men from Detroit slept and ate on the plant's premises while putting in twelve-hour days, seven days a week.
• The team got the first Miller-Ford racing car to the Indy Motor Speedway on May 12 of 1935.  One of the last racing creations of Harry Miller, the genius of the sport in this country, the Miller-Ford created even more of a sensation than new Millers had in the past. Low, rakish, and unbelievably streamlined in almost every detail, it was beautiful beyond all anticipation, perhaps the prettiest thing of its kind ever seen in this country.
• The compact transaxle provided only two forward speeds, with low gear equivalent to about 80% of the speed obtainable in direct or top gear.
• The four-wheel independent suspension itself was probably the most striking feature of the car.  It was, and perhaps still is, the most aesthetically appealing suspension ever put upon an open-wheel car of any type, and stands next to certain of his engines as the outstanding example of the Harry Miller touch.
• Another innovation on the Miller-Ford chassis was an epicyclic steering gearbox. Unfortunately, placement of that gearbox and the steering column U-joint near the engine's cast iron header was the cause of all the problems of the Miller-Fords upon their race debut.
• The cars possessed the smoothest exteriors of any race cars ever built anywhere.  Such items as leaf springs, drive shafts and brake cables are enclosed by streamlined duraluminum arms.  The steering linkage is inside the frame and the flat rectangular (12” wide, 1 1/2”deep, 6' long) exhaust pipe is streamlined into the steel floor.

• Engines were ordinary 1935 “21 Stud” side-valve V-8 blocks of 221 CID, turned backward in the frame to drive the front wheels.  Blocks were ported, had non-standard four-ring pistons and racing cams, but were otherwise completely stock internally.  High compression (9.5 to 1) Bohnalite aluminum alloy heads were fitted, as were aluminum intake manifolds with four single-throat carburetors, although a few had two dual downdraft carbs.  These engines were typical of many hot rod V-8s of a few years later and were good for about 150 bhp at 5000 rpm.
• The cars were fitted with speedometers in place of the conventional tachometer.  
• By previous arrangement, all cars would be entered in the Indianapolis 500-Mile Race by Harry Miller.  Some reports indicate just eight of the ten cars were actually completed prior to the race, and of those perhaps only five were in condition to complete qualification runs.  Speed in practice was better than 130 mph.  Four of the five Miller-Fords qualified, with speeds ranging from 110.519 mph to 113.213 mph.  Drivers found that the V-8s were not particularly powerful but that, thanks to the fine chassis, they could lean on them all the way around the track.
• None of the four qualifiers could finish the race, due to steering gearbox failures and lock-up from excessive heat buildup.  This fault emerged during the cars' practice and qualifying runs, but attempts prior to race day to mitigate the excessive heat buildup were fruitless.
• After the race, the entire fleet of Miller-Ford race cars was confiscated by Mr. Ford and locked / stored in one of the back rooms of Ford's Highland Park plant for more than two years.  Sometime in late 1937, certain friends of the company were able to buy them.  Most new owners then installed Offenhauser engines in place of the Ford V-8s.  In 1938, Herb Ardinger drove a Lew Welch-owned Offenhauser Special Miller-Ford to sixth place at Indy, and Cliff Bergere drove that same car to third place there the next year. 
• Several of the other Miller-Fords also returned to race at Indianapolis through 1947 with a variety of engines, including the DOHC Winfield Novi V-8 and Ford's venerable side-valve V-8. A side note from the 1947 Indy 500-Mile Race (as recounted in the book “Indianapolis 500 Chronicle”):

“Perhaps the longest shot in the 1947 race was the Miller Ford entered by the Granatelli Brothers, Andy, Vince, and Joe.  After all, the car was 12 years old and driver Pete Romcevich had heretofore never risen much beyond the midget ranks. But by 20 laps, “Pistol Pete” had charged the flathead Ford V-8 from 17th to seventh.
“On Lap 30, Romcevich pitted with the granddaddy of all oil leaks and little or no oil pressure.  Realizing the rule against adding oil once the race had started would disqualify the car, Andy Granatelli yelled for his brother Joe to bring the water bucket.  In full view of officials and fans, Andy removed the radiator cap, placing it purposely onto the radiator shell.  Leaning in, he blocked the official's view, while he quickly removed the oil breather cap and dumped two gallons of water into the crankcase.  The water mixed with what oil was left in the engine.  The nonplussed Pete and Joe watched the oil pressure return to normal.
“Back in the race, Romcevich drove at a slightly reduced pace.  The car lasted another 138 laps before the engine tore itself to bits.  Nevertheless, the old racer finished 12th.”

Sources:

• “Ford: The Dust and the Glory, a Racing History” by Leo Levine
• “Indianapolis 500-Mile Race History” published by Floyd Clymer
• “Indianapolis 500 Chronicle” by Rick Popely with Spencer Riggs