reliable devices, and in making these components, the Ford Motor Company engineers used, from a modern perspective, extremely high levels of over tolerance to assure endurance of the end product. Since it was up to the end-user to effectively finish what Ford's assembly line left unfinished, while ingratiating him with munificent amounts of material to work with, the Ford Model T gave birth to the modern aftermarket performance engineering market. Later, with the introduction of the Model A, Ford's flathead V8 in the early 30's, and their ease of availability in the post-war 1940's and early 1950's at a price that was within the reach of teenagers, mating one to a salvageable example of a Model T or a Model A lacking this eight cylinder engine gave birth to Hot Rod culture in the early 40's. Internal design The T engine was an inline-four, with all four cylinders cast into one engine block. Such monobloc design was an uncommon practice when T production started in 1908. It lent itself to mass production, showing the Ford company's prescient focus on design for manufacturability. The head, however, was detachable, which not only aided Ford in manufacturing but also made valve jobs (cleaning, grinding, or replacement of the poppet valves) easier. The block and head were both of cast iron. The engine's bore was and its stroke was even, for a total displacement of . The compression ratio was 3.98 for most engines; early engines were slightly greater. This value is low by modern standards but was typical for the era, making the engine forgiving of poor-quality, low-octane fuel and minimizing cranking effort at starting. The valvetrain was a side valve (flathead) design. The crankshaft had 3 main bearings. Cooling system The T engine's cooling system reflected the T's simplicity design theme. The first few hundred Model Ts had a water pump, but it was eliminated early in production. Instead, Ford opted for a cheaper and more reliable thermosyphon system. Thermosyphon was a common engine-cooling method of the era. Hot water, being less dense, would rise to the top of the engine and up into the top of the radiator, descending to the bottom as it cooled, and back into the engine. (This was the direction of water flow in most cars which did have water pumps, until the introduction of crossflow radiator designs.) The thermosiphon system was susceptible to overheating if worked