512 Block Date

[rubbinisracing]

I,m trying to figure out from what date code going forward you can be sure that a 512 4-bolt (not CE) block was built as a 454 and not a 427.

Example: block casting date of 12/20/69 was it built as a 454 for an LS6 or were their 427's still being put in copo's or some other usage I'm not aware of. I know 69 Corvette production ended in December of 69. Again I'm referring to vin stamped blocks.

I know you guys know this, I'm trying to get a "cheap" education.

Thanks in advance!