Can I assume Nov 10th 1967, then. A body 383 engines weren't cast way back in the past because they were unique to A bodies, and because of low production. so the cast date will be likely closer to the month of production, and year.. Don't worry, your lucky to have an A body big block. I did read where some early 68's didn' t get the VIN# stamped on engines until Jan 68. I don't know if that is true. my 68' GTS 383 is not stamped HP, but has the correct VIN# on the block and transmission. Mine was cast 11-30-67,and stamped as built on 2-11- 68. The actual assembly range can be a few days to week . However, These cars are so rare, the most Important thing is that the engine is the A body 383 engine. they are different than a normal 383 in a B or C body. To verify, Look on the driver side behind the accelerator linkage and see if there are six digits on the lip of the block.Then there should be the same numbers on the transmission lip.If all else fails, look for the motor mount driver side, and there should be only one ear for the bracket. Very Obvious!