Remember, the date code is on the back of the motor. The date code will be located to the left of the distributor (if your standing at the back of the motor) on the flat spot of the blockwithin a few inches. There will be 4 small numbers which are raised castings. Wire brush is sometimes needed to get the gunk of the area to see them properly. Good luck.
Also, in that area will be another set of numbers which will have much bigger size and be maybe 6-7 digits long. This is the actual casting number. It will tell you what the engine is. When you find these numbers go to the wallace engine website and the numbers can be decoded there. There are other places which have the decoding information that's just the one I used recently.hope it helps.