Perhaps the vac. retard on my 1800E isn't working very well, but when it is connected the engine has a huge dead spot coming off idle. It just seems to take a second or so to come to life, which makes certain traffic situations a little more exciting than they need to be. With it disconnected it has immediate pep off the line, no delayed reaction.

For a true mechanical advance only dist try scrounging up a Mallory unit - I saw one (a dual point) on eBay just yesterday. Although the vacuum retard ones work perfectly fine with no vacuum attached.