318 Engine stumble

36@3600 is the same as 36* at 3600 and not the same as 36* at any other rpm..... unless the timing lite says so.

With the Vcan removed, check the timing every 400 rpm from 3600 down, namely 3200/2800/2400/2000/1600. Plot those numbers on a graph with rpm along the bottom and advance up the side. Next connect the lowest three dots with a straight line, averaging up the middle. Then the top two get connected. Then extend the lines until they cross or meet. Now you have a pretty good idea of what your timing is from 1600 to 3600.
There is nothing wrong with 36* at 3600 unless it appears on the same graph with less than 10* at 1000rpm. If that appears on your graph, then yes, you will want to reduce the flyweight travel. Then rev it back up to 3600 and twist the D to get 36* again, then check the idle timing. If it is now more than 10* and less than 16* you done good. If you are targeting a specific idle timing, like say 14 but you only have 10, then you will have to limit the flyweight travel some more, and again retest.
With 36*@3000 timing, you may have to run premium gas to keep her out of detonation.I would not be in a hurry to try and run that.
In a streetcar; You will not likely feel the difference from 36* to 34* with your butt dyno. Maybe your butt-dyno will not feel the difference from 32* to 36* either. This is because the vast majority of the time, you will not be at WOT, and will not miss 3 or 4 or 5 horsepower at 3600 rpm. Your right foot will just drive that many horsepower deeper into the throttle. You would have to have a pretty small engine to miss them. After all; 5/150~3.3% at the low end of the scale and just 5/230~2.1% at the higher end.
So sneak up on the power-timing. Don't be afraid to take several days or even weeks. Get to know your engine and the sound of NO-detonation. Then you will hear, and maybe feel, detonation if it comes.
Detonation must be avoided at all costs.