Someone here(not me) should be able to identify the year and other info on the block.
With the engine being blue, and apearently not repainted, it points to it being a Passenger engine. Truck engines were for the most part a bluish-gray, although manual transmission Passenger engines were also that color. Like Jordan noted, there is a number stamped on the machined pad just behind the distributor. If there isn't a number there (factory replacement engens were't stamped), there also are several casting numbers that can help ID it. One is the block casting date, which is located on the right side of the block, right behind the starter. There's also a part number cast on the same side of the block, but further toward the front. The head castting number will be on the LF portion of the head, on the top ledge fairly close to the lip of the rocker arm cover. Any of those will get the approximate year/application, but the stamped ID number by the distributor will peg the exact original application.
