in 1965). These new chassis allowed for reduced weight and smaller body sizes. The similarly styled Chevrolet still used the "X" frame from the early 1960s. A new compact Tempest was introduced for the 1961 model year. It was one of the three Buick-Olds-Pontiac (BOP) models introduced that year, sharing the platform with the Buick Special, Skylark, and Oldsmobile F-85. A four-cylinder engine was also introduced in the Tempest model line. All three BOP cars were unibody, dubbed the Y-body platform, combining the frame and body into a single construction, making them comparatively lighter and smaller. All three put into production new technology pushed by John DeLorean, on which GM had been working for several years prior, but the Tempest was by far the most radical. A flexible steel shaft rotating at the speed of the engine delivered power from the front-mounted engine through a "torque tube" to a rear-mounted transaxle. This provided close to a 50/50 front-rear weight distribution that improved handling as well as incorporated four-wheel independent suspension. The design almost eliminated the large floor "hump" common to front-engined, rear-drive cars. Though the Tempest's transaxle was similar to the one in the Corvair, introduced the year before, it shared essentially no common parts. GM had planned to launch a Pontiac version of the Corvair (dubbed "Polaris"), but Bunkie Knudsen—whose niece had been seriously injured in a Corvair crash—successfully argued against the idea. The Polaris design apparently made it to full-scale clay before it was canceled. Instead, DeLorean's "rope-shaft" design was green-lighted. The Tempest won the Motor Trend "Car of the Year" award in 1961. Toward the end of 1961, an upscale version of the Tempest called the LeMans was introduced. The Tempest featured a inline slant-four cylinder engine, derived from the right bank of Pontiac's 389 V8, enabling it to be run down the same production line and reducing costs. the engine received a crankshaft designed for four cylinders, but this did not completely solve its balance issues. The engine gained the nickname "Hay Baler" because of its tendency to kick violently, like the farm machine. An optional Buick V8, was not popular when it was available for 1961 and 1962 in the Tempest. For 1963, Pontiac replaced it with a new "326" that was actually V8 with a bore of 3.78 and stroke of 3.75 (same stroke as the 389). It was based and shared parts with