Properly-working vacuum advance is always beneficial to performance. Many times it's left off because there are no provisions for it and/or the distributor has too much vacuum advance, as some ZX distributors may.
What is the model number of your 45DCOEs? It will likely be either a 9 or 152. The good news is that the 45DCOE152s actually DO have provisions for ported vacuum! I was very surprised to see them when I got my 152s. You can gang up a few ports and have a decent signal. The possible not so good news is, as I mentioned earlier, that your particular ZX distributor may have too much vac advance for a non-EGR engine. You'll have to let us know the distributor part number off the body to be sure. It'll look something like "D6K8-xx" or a permutation thereof.
Otherwise, running manifold vacuum for advance will give you a lot of static timing, likely more than your engine wants. It can probably be made to work though if you really want to. As someone else mentioned up top, check out 123ignition. They're programmable distributor is a fantastic solution (or so I hope)!