I have an all original 68 Z/28 with a build date of April 1st week 68, but the engine blew, beyond repair, so I need a block and 1 head. The good head has a casting date of C228(March 22 1968). Pitched the block sometime back and don't have the numbers on it. So I'm thinking the block should be dated around the same time as the head, give or take 1 or 2 days. The block casting should be 3914678 and I've been searching for 6 months and the closest I've found is March 8 68 and Ive found a pair of 3917291 heads with March 13 th and 28 th dates.