Pontiac had an SD engine program in the late 50s early 60s, and later/briefly again in 1973/74 with the SD455. This video is regarding the FIRST Super Duty program.---In only a few years time during the late 50s early 60s, Pontiac MORE THAN DOUBLED their V8's horsepower output (described in this video), while using/keeping the same V8 engine block they used thru 1955-81. Even though the same block was kept, from 1955-62 the cubic inch displacement grew much larger than the initial 287 cuber it started as in 1955. It grew to a 317 347 370 389 and finally a 421 cuber in 1962. It eventually maxed out at 455 cubes in 1970. By 1970 ALL the other GM divisions were producing engines at 454 or 455 cubes (500 for Cadillac). PONTIAC WAS THE ONLY DIVISION still using the same block they used in the 1950s on engines that had a much smaller displacement -- 287 cubes. The 1955 287 displacement would remain the smallest displacement ever used in the Pontiac V8 block all the way until 1980/81 when a 265V8 was produced. Since less durability was required for the smaller displacement, the block was decked/butchered/lightened on the 265/301v8s of 1980/81. Prior to 1980 the block had never been decked/butchered/lightened. The 1980/81 265/301v8 blocks were about 200 pounds lighter than the 1955-79 blocks, and only 25 pounds heavier than a Buick 231V6.
2 мар 2010
