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The A311 Racing Hemi Program and Chrysler’s Indy Effort

racing hemi engine - chrysler a311

The A311 Engine program was first begun to provide Briggs Cunningham with an engine for his All-American attempt to win at Le Mans. Although he never succeeded in his quest he did come close several times. Failure was never due to his engines, though their extra weight certainly contributed to the brake problems which plagued him. This is a story in itself for later.

The A311 was a full blown effort to make the 331 cid Firepower V-8 competitive with the Jaguars and Ferraris at that famous Sarthe Circuit in the 24 hour race. It had a gear driven camshaft with roller tappets and some pretty wild overlap and duration figures. The compression ratio was around 12:1 and the racing pistons were all aluminum (without struts) and fit very loosely. Induction was Hillborn injection with tuned velocity stacks. I believe there were some multiple carburetor versions for Mr. Cunningham.

It goes without saying the ports were cleaned up and the much-discussed hemispherical combustion chambers were polished. Dual valve springs with surge dampers were used with special pushrods. Exhaust was welded from large diameter steel tubing. Later engines used a breastplate between the block and oil pan as very high output testing revealed a lack of stiffness in the bottom end.

A311 Mopar hemi racing engine

The 331 cid tested earlier at Indy was so fast it scared all those established interests to death. They rapidly changed the rule which had allowed a larger displacement to be used on production-based engines. Mickey didn't get his until 1962. The photos show a late model A311 of 271 cid (but still the Chrysler block) as tested at Indianapolis in 1952. Although competitive, the car was not a winner as the earlier test work with a 331 cid A311 had predicted.

In his history of the Chrysler hemi, Curtis Redgap wrote:

For all his stoic outward appearance, James Zeder was immensely proud of the Hemi engine. He also had a desire to see it be used in racing applications. He had an eye on the Indianapolis 500, the greatest spectacle in racing at the time. He had the lab begin experimenting with the 331 Fire Power.

John Platner and Don Moore were deeply involved in building the "Indy" engine which received the designation of A311. It was built with 8 Hilborn fuel injectors, big valves and ports, streamlined big exhaust manifolds, and a modified camshaft that made the engine make "burbling" noises at idle. Under the guise of testing tires for Firestone and Goodyear, the engine was installed in an Indianiapolis special racer. With the A311 engine, it easily ran the same lap speeds as the specialized Offenhauser and Miller racing machines.

The true opportunity to put the A311 to the test came in June of 1954. Shortly after the running of the 1954 Memorial Day 500, Chrysler Corporation dedicated its Chelsea proving grounds. The first four finishing Indy drivers were invited to bring their racers over to christen the 4.7 mile long oval race track. With wide lanes, and banked curves, the drivers were able to hold their cars wide open all the way around. The single fastest lap that day was made at 179 miles an hour. Then the Kurtis Kraft tire test car with the Hemi A311 made a couple warm up laps. Coming out of the 4th turn, the driver opened the engine up. It screamed by the centrally located pits and timing stand. Its deep Hemi bellow could be heard all the way around the long track. When it went by the next time, it was rolling at 182 miles an hour. And then did it again, and then again. Mr. Zeder and his engineers were delighted. They knew that a stock block engine with push rod technology could easily compete at Indy, and most likely, easily win.

It was not to be. The news of the test was given wide publicity. In a flurry of activity, the engine size rule was changed to allow only a 272 cubic inch limit for stock engines. A slight increase in piston stroke easily achieved the 272 size. However, down on power, it didn't qualify. It would not be the first time that rules were changed by sanctioning bodies when Chrysler came out to play.

A311 engine

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