Sorry trucks, but Im not a chevy man. The olds 400 Big Block was built from 1965-1969. However, in 1968 they decreased the bore size(3.870 I) and increased the stroke. makes for a horriblly undersquare motor. However, the 403 was made from 1977-1979. Large bore (4.351 I) and short stroke. However, suffers from windowed mains and siamesed cylinders. As such, not a very efficent cooling motor, nor is it capable of wihstanding high Rs without some type of lower end enforcement. Oh, and I also dont appreciate the "Brainwashed" comment.