2457772 does not correspond with any 911 engine series I know. The first few years were the 9xxxxx serial series, then in 1968 the xx8yyyy serial series, and from 1969 they always start with a 6. What is the engine type #? I'm certain that is a magnesium case, so what are the cast in part #'s below the oil return tubes on both sides? That will help establish a date of production.
http://www.early911sregistry.org/for...case-Revisions
