The only thing I can find is a 1966 327/185 (2BBL and manual transmission) from a C60, M60 or S60 truck. However, that can't be right since Flint used the F designation until 1967, then they went to the V. Your's was assembled on October 10th, but what's the casting number and date on the block?
It came from a truck for sure, but the casting number and date will verify the year.
Ed