A customer had concerns about whether he had the original C-code 289 engine in his car. He was pretty sure the manifold was a 1968 302.
I urged him not to get too hung up on the “date coding” unless he was after a concourse car – which is way more money than anybody should have to pay. The 289 & 302 have all the same major components (basically the same engine) with different cranks. The 302 crank provides a slightly longer stroke & raises the displacement a whopping 12 inches. Don’t worry about it.