Hello people, I am working on a cylinder head for a friend and cannot reach him as he is deployed, he is supposedly working on a 1951 buick, dunno what model, but it is a straight 8, casting number 1340827-2, am trying to locate exhast valve specs and maybe valves, none of my manuals go back that far for buicks, but do for just about everything else, is there anyone that can help me? thanks in advance.