This question has been on my mind a lot lately and I haven't been able to get a real answer. This is the scenario I experienced. A stick of truss was bolted to a truss plate. Bolts go up through the bottom of the truss plate and nuts go on the top. Following this lead all the truss bolts then went through the bottom of the connections and had the nuts place on the top. However when I got to the top to put on a corner block on I was told that "the bolts have to go down for strength". Is it really for strength? How much does direction of the bolts matter in these situations? And isn't better to place the heads of the truss bolts inside the corner block because its so hard to properly tighten nuts placed on the inside of a corner block?