OK, that engine is a Chevy V8, not sure of the size. According to the data plate, the truck was originally equipped with a GMC 270 inline six. If you look on the engine block just ahead of the passenger's side cylinder head you'll find a machined pad about 1/2" wide by 3" long with some stamped numbers. Post those numbers, including any letters at the end of the sequence, and one of our friendly number crunchers will be able to tell you the year, the size, and the original application of the engine. If the pad is blank, there's a possibility it's a "Target Master" replacement engine that was sold through GM parts departments as a new alternative to the rebuilt engines sold by local machine shops and distributors like Jasper and other high volume rebuilders. Good luck with your restoration.
Jerry
