There is no way there is a factory 1970 427 Nova. There is not a 1970 or later Chevrolet made ever that had a 427.. (no tall deck truck motor cracks please)... 454 replaced the 427 for '70. And there was NEVER a factory 454 Nova made....ever.... So there goes all those theorys.. Show me a big block 427/454 engine "COPO" swap made after 1969... in anything
you can't