I got it running today.
Here's how I checked the accuracy of the 4* advance:
With it at TDC, I installed the chain in the 4* advanced position. and moved the crank (without moving the cam), until the gears and chain went on. I temp installed the timing cover and put the damper on far enough to be sure it was on the key. The timing mark moved 4* from TDC.
It seems like it idles a bit better. I had to richen the mixture screws almost a half turn. The vacuum is still low; about 6". Timing is at 35 total, as it was before. Initial is as it was before too, at about 30* (The 1200 rpm idle brings that in.) The test drive felt about the same as before. A trip to the track won't happen until September or October. Maybe that'll show something, maybe not. It cranks slow when it's hot. It did that before. I have an ignition kill switch for that.
I just realized I didn't check PV clearance. I know there was plenty when the cam was straight up. I got lucky.
Here's the compression test I did before the advance (both tests w/ engine warm, throttle open)
1) 180
2) 170
3) 185
4) 185
5) 170
6) 180
7) 170
8) 170
Here's a test I just did today after advancing the cam:
1) 150
2) 155
3) 175
4) 150
5) 150
6) 135
7) 155
8) 145
Something tells me I need a new compression gauge. There's no consistency. Plus, I would think the numbers should be higher with it advanced.