The Slant Six started with a packaging constraint. Chrysler's new compact needed a low hood line and the inline-six was too tall to fit under it. Leaning the block 30 degrees to the passenger side dropped the overall height enough to make the car work. That was the goal. Everything else was a side effect, and the side effects turned out to matter more than the original problem. The first one was the intake manifold. With the engine tilted, there was suddenly open space above the block on the driver's side where a manifold could go. Chrysler used it to build long, equal-length intake runners that would have been impossible to package with the engine standing upright. Long runners raise air velocity at low RPM and produce a ram-tuning effect where pressure waves in the runner help pack the cylinder. The result was strong torque well below 2,000 RPM, which is exactly where a taxi, a delivery van, or a family sedan actually operates. The second was the exhaust side. Tilting the engine one way pushes the exhaust manifold the other way, which gave the exhaust more room and a straighter path out. Better breathing on both ends from a decision made purely about hood height. The third was maintenance access. With the block leaned over, the entire driver's side of the engine faces upward. The spark plugs, the distributor, and the fuel pump are all sitting where a mechanic can reach them without contorting. A generation of owners learned basic engine work on Slant Sixes partly because the engine made itself easy to work on. Then the hardware underneath. The 225 used a 3.40-inch bore against a 4.125-inch stroke, heavily undersquare, which produces torque at low RPM for the same reason a long lever moves a heavy object more easily than a short one. Cast iron block and head. Hydraulic lifters that never needed adjustment. Moderate compression that ran on whatever fuel was available. Four main bearings on the early engines, later seven, supporting a crankshaft that was massively overbuilt for the power it was making. That overbuilding is why the durability stories are not exaggerated. An engine making 145 horsepower with a rotating assembly specified for far more never approaches its own limits. It just runs. Taxi fleets in New York, delivery companies, farm trucks, and families who could not afford to be stranded all ended up with the same engine, and the engine kept starting. Then the performance chapter, which almost nobody expected. Chrysler built a factory hop-up package called the Hyper-Pak with a four-barrel carburetor on an even longer ram-tuned intake, a hotter camshaft, and higher compression. The Hyper-Pak Valiants swept the compact car race at Daytona in 1960, finishing ahead of every competitor in the field. Offenhauser and others later sold multi-carburetor intakes, headers, and cam upgrades to anyone who wanted them. The Slant Six ran in American cars into the 1980s and continued in trucks and marine and export applications well beyond that. It is remembered as the engine that would not die, and the reason is that Chrysler solved a hood clearance problem in a way that accidentally made everything else better.