I have a motor I pulled out of a 69 Impala. The engine suffix is HN which shows it go be a 300 HP 350. The serial number is 19L044219 which shows it to be a 1969. Heres where the confusion starts. There is no date cast in to the usual place on the rear of the block or anywhere else on the engine in the usual format. On the right side of the block the numbers 9 3 and 7 are cast. See pic below. Is this actually a casting date in another format? Was hoping someone can shed some light on this.