Just an FYI: I closed in on a ZL1 this morning out here at the swap meet.
The Block was actually rather nice; no repairs at all and I looked it over quite closely! However: It had the number "2" in the 3946052 casted smaller than the rest of the prior 6 digits. It was definately not redone and after much thorough closer observations noticed NO date codes on the side walls on either side! The aluminum casting had never been tampered with. The 074 heads that were with it were dated 74 and a day apart! I have seen the smaller "2" digit before but not on a block missing the actual date codes! Just Converstaion here...