Jim, I deleted my post because I was confusing your overdrive cars with the C-6 2.75 car
With the 2.75 C-6, I'd advance that cam to 106 with an 8.09 DCR without thinking twice. I run 89 all day long with my 489 at 8.33 with alum heads, 8.09 isn't bad at all. I wouldn't hesitate to run mine on 87 if required.
The second thing you pointed out, that curve needs some help. Get that poor FE to closer to 14 initial and 36 total all in by whatever you think it can handle, I'd shoot for 3000 because of the tall gear and the fact you'll be starting at 14 (plot the curves you'll see what I mean)....but dont ignore vacuum advance, a lean motor needs more timing and when you are cruising it should come up to the 44-48 range when you add vacuum.
WOT mechanical plus initial is only a dyno and racing tune, you want more timing in lean conditions at low load like steady cruise.
Both the increase in initial and the earlier cam timing will raise vacuum and make it more efficient. Although your peak numbers look better, the part throttle difference will be even greater, it will be nearly magical.
Matter of fact, if you didn't have compression limits, I like a 104 ICL with that motor, it would really bring the part throttle performance around.
After you get that squared away, you could also consider playing with the primary metering block for additional gains.
Reducing primary jet size as low as it can go, but adding back PVCR to give it the fuel under load can bring even more gains, but probably not worth doing until you get those cylinders filling effectively with better intake lobe timing.