1970 L78 Nova SS owner needs feedback.

[Ls6 Ragtop]

I have never heard of any 70 L78 engine having anything other than the 569 intake and 291 cylinder head, on a Chevelle or a Nova whatever. I don't claim to be an expert on Novas but the flat top 3 in the V.I.N. is not the only thing I have question about on the engine stamp. Maybe somebody with a known original engine in their Nova can compare the W on their block and see if it matches this cars. I personally think the trans stamp is good, you can even make out the 1 in front of the 0 if you look hard enough, but the engine stamp has a few things I don't think are right.
Chris