only tiny recesses for the valves. This arrangement was achieved by combining a cylinder head deck that was not perpendicular to the bore with a crowned piston, which was a novel concept in American production engines of the day. As the piston approached top dead center, the angle of the crown combined with that of the head deck to form a wedge-shaped combustion chamber with a pronounced quench area. The spark plugs were inserted vertically into the quench area, which helped to produce a rapidly moving flame front for more complete combustion. The theory behind this sort of arrangement is that maximum brake mean effective pressure (BMEP) is developed at relatively low engine speeds, resulting in an engine with a broad torque curve. With its relatively flat torque characteristics, the "W" engine was well-suited to propelling both the trucks and heavier cars that were in vogue in the US at the time. The W-series was a physically massive engine when compared to the "Small Block" Chevrolet engine. It had a dry weight of approximately , depending on the type of intake manifold and carburetion systems present. Compared to the 283 "Small Block," it measured 1.5 inches longer, 2.6 inches wider, and 0.84 inches less tall. General Motors engineers explained, in 1959, reasons behind the combustion-in-block setup. Anticipating varied future compression ratios in future auto and truck use: "It was obvious that with the combustion chamber placed within the cylinder head, the foundry must retool every time a compression change is in order. The necessity of making special heads to provide a range of compression ratios and to permit attachment of accessory mountings for the various model applications is of serious concern to the manufacturing and service departments....Inclining the top of the block to 16 deg and shaping the top of the piston like a gabled roof with a 16-deg angle resulted in a 32-deg wedge-shaped combustion space....The addition of two milled cutouts [in the head] to extend the volume of the combustion wedge can create a compression ratio of 7.5/1; one milled cutout produces a 9.5/1 compression ratio. The difference between the volume of these cutouts provides a wide compression range without making any changes in the piston or cylinder head. The number or size of cutouts is varied simply by adding or removing cutters." 348 The first iteration of the W-series engine was the 1958 "Turbo-Thrust" , originally intended