If I could just come up with a buildable block, I am sure I could come up with the rest. I actually have a std bore rotating assembly for a 409 with a fresh crank, original forged 11:1 pistons (with a few spares) and a set of rods. The only block I have is a 348 truck block that was bored to standard 409 bore size. The man I bought it all from (about 10 years ago) said it passed sonic check after the overbore. Everyone on here said there is no way that could be correct or that it will live so I never put it together. Sometimes I think I should just do a half fill with some block filler and throw it together and let it rip for as long as it lasts. LOL
A sonic test doesn't cost much, why wouldn't you take it and have it checked?
Bill