There's nothing wrong with it it's just that different years they did different modifications to the primary plates. The original one is probably the one with the big hole in it and the oil will drain back into the primary just fine. The one with the smaller hole is probably the one you just bought. The small hole in the bottom of it is to drain the oil back into the primary. Otherwise it'll go out to the starter. As long as that hole is in the bottom of the trough when the primary is sitting flat you should be fine. Remember only 22 oz of fluid goes in the primary when you put it together
