[rpoz11]

Hi...

In this forum and others, it's generally known what most of the proper casting numbers, date codes, part numbers etc are to recreate a copy of what was original equipment for original COPO and ZL1 cars.

Maybe most are overlooking your inquiry because most of us know what it takes to make one.

I think it is of relative agreement that one should use the more recent reissue ZL1 blocks with all of the updated revisions GM did to it to be stronger and survive without failure.

You need to ask yourself:
Do you want a visually correct Appearing engine?
Or do you want to have a BB motor that is going to satisfy your end result without original part numbers,etc?