Obviously an MO coded 302 engine, a Muncie Aluminum cased transmission, a 12 bolt rear axle with gears higher than 3.55 (3.73 is by far most common), 4 leaf rear springs. front disc brakes, 15 inch wheels. Thats about it, but you need to be able to tell that those things are original to the car, or have been added over time. Look at the codes on everything and make sure they all go together, look for original tire stickers on the glove box door, tag on the radiator, codes on the alternator etc.