[PeteF]

Update: I checked the intake manifold bolts, and they were indeed under torqued. All around 15 ft-lb, should be 25. So, in sequence, I brought them all up to 20, then up to 25, and was feeling pretty good at that point. But, after start and warmup, still 9 - 10 in-Hg at idle. I then advanced the initial timing to the max 34 degrees, to see if vacuum would increase, but 10 in-Hg is all she will pull. My next step is to my local trusted mechanic, to see if he has any ideas. Will also look into the pyrometer idea mentioned here. I guess it's possible that the intake gaskets are compromised and just retorquing may not be enough........or there is some other leak source I haven't found.