OK, I have both pumps here and did some measuring. The older 7 tooth pumps have a gear depth of 1.24 and the newer style 8 tooth pumps depth is 1.30. I then placed an 8 tooth gear next to a 7 tooth gear adn the heigh difference is noticeable although very very small. The height of the gears is 1.20 for the 7 tooth and 1.26 for the 8 tooth, same difference of 0.60. If I can get a camera I'll take a pic of the height differences to go along with the other pics I took in my previous post. I also measured the width of each gear, the 7 tooth is 1.47 wide and the 8 tooth is 1.67 wide.
The valley where the gears reside is also quite a bit larger on the 8 tooth pump, the 8 tooth being 1.73 wide and the 7 tooth being 1.625 wide, but the largest difference is in the length of the gear valley, the 8 tooth being 3 inches across and teh 7 tooth being 2.765, when you see them next to each other the 8 toth pump is quite a bit larger gear wise.
I'll see if I can put these figures onto a pic to better describe them.