What Engine Is This?

Correct.. but the topic was how could this be 66 318 LA

The casting date of a part can be from the calendar year BEFORE the actual model year.

I think I answered it pretty well, was cast in 1966 for a 1967 model year car...

It shouldn't be so hard for people to understand.

I think we are splitting hairs here. We know its for a 67 but it was born in 66. Thus the 66 casting date and 65 part #

Cars and parts are not "born". They are cast, forged, molded and assembled.
This engine block was cast early enough to be for a legitimate early 1967 year model car.
Rick Ehrenberg often said that a proper date coded engine should be no more than 2-3 months older than the build date of the car and certainly no closer than 1 month.
I did have a 440 that I pulled from a 1971 Chrysler 300 that has a November 1969 casting date. It was the original engine. That was the longest span between casting and installation that I have heard of.