B&M Megashifter?

Now that I have the engine ironed out it is time to move on to other problems. After I installed the tranny and Megashifter I can't get 3rd gear. I have a 727 with a manual reverse valve body. The problem is not that it hasn't got 3rd gear. The problem is the shifter will not allow it to go to 3rd. I set the shifter up with the tranny in park and the shifter in park. I am thinking that my stock lever on the tranny is to long to allow the shifter to pull it all of the way. This was a used shifter in very good condition but I didn't get any instructions or the tranny lever. It rachets properly.
Has anybody got any other ideas?

Jack