To further clarify, 109 is actually the last three digits of the block casting number, found on the side of the block. It is vissible from underneath the car.
The D5 is a stamping found all around the perimeter of the stock torque converter top. Various two digit codes helped identify the many internal converter configurations for different vehicle applications. Word to the wise though: Converters are often cut open and reworked so the two letter code may not mean anything at that point.