1958 Olds 371 Timing and Vacuum Advance question
I have a 1958 Olds with a 371 2 barrel. When I got it it had a dead cylinder, low on oil, and vacuum problems. I fixed most of that, but it still wants to struggle when sitting still and in gear. In park or neutral, it almost feels and sounds normal, but the extra load makes it shake when you put it in drive. When I fixed the dead cylinder (plug wire), I thought it might shape up. It obviously helped a lot, but I am still looking for more. I am not a mechanic, and I'm finding it hard to find too many guys in my area that are interested in doing much looking at it. I actually had a couple of locals do a little tweaking, and neither found the plug wire, so as I said, I don't think their "hearts" were in it.
My question is, I was reading an older post on here about timing, vacuum advance, ported vacuum, and manifold vacuum. The guy that had this before me did some jerry-rigging on a lot of stuff, and the current set-up uses ported vacuum. However, I discovered yesterday that the old vacuum advance can is bad anyway, and have ordered a replacement. I would like some more expert opinions on the subject of getting this correct. I plan on trying to set the timing again, vacuum advance disconnected, and then reconnecting it to the best source. Some of the guys said that manifold vacuum really gave them a boost, but I would like to hear some more about it. I realize there could be more issues, such as compression, rings, valve issues etc., but I would like to at least give it the benefit of the doubt and do what I can first to see if I could get it to be a daily driver.
Thanks to anyone who might have an idea or two.