Our block is a '77 version, although Landy states quickly that no particular vintage block is much better than any other. The later-year blocks did have this strengthening rib cast along their sides, which doesn't hurt, but wasn't worth any huge strength increase. We'd heard the '67-72 "HP" blocks were the hot ticket, and we'd also heard about higher-nickel content in '68 blocks, but Dick told us none of this is true. The two-bolt mains have been fortified with studs, but that's about it. The mains were cast deeply into the block, which does help the two-bolt mains support big power.