Rochester 2GV Bad Hesitation

First off, if it's a stock engine, it does not have a lot of manifold vacuum. A healthy stock engine...and even a slightly modded one should have about 19-21 hg. What you have may sound close, but it's low. I think the timing may be either too low or something is amiss in the distributor causing it to give a low timing signal. Low timing is the number two reason for a low vacuum reading right behind a vacuum leak. I would start by checking the initial timing and playing around with it to see what it does.