With the motor being in the car how can you tell if its a 318 or 340 motor , where are all the identifying numbers for this, any of them easy to get to

look on the front of the block on the dr side just below the head gasket (might have to wire brush it off) & check the small stamped #'s. There's also large cast in #'s on one side of the block but in the car it MAY be hard to see them & this is easier

Although all factory 318/340/360 small blocks are the same size and shape looking basically the same on the outside, you can tell them appart by looking at the assembly and casting numbers. Look at the front of the block under the drivers side head, there should be numbers that are stamped there that will id the engine, otherwise you'll have to crawl under the car to read the casting number on the side of the block. Blocks assembled after 1972 may appaear different in the black stamping area pictured, that's when the casting numbers are more helpful.