small block water pump bolt length?

Hi, Can some one tell me the correct length water pump bolts, the two on the bottom, I bought a timing cover and water pump bolt set from mancini and the two bottom water pump bolts are to short, they are 2", one of them will thread in about a 1/4", and the other not at all, I just want to make sure that when I get longer bolts that they do not go to far in to the opening of the timing cover. Thanks, Jeff.

What water pump are you running, the 60's style cast iron pump, or the 70 and later aluminum????