How about I jump in on this bandwagon.....
I believe you live in Sonoma? I live in Petaluma and work in Napa so I pass your way twice a day. I would be happy to pull the carb off my '69 Z/28 (which runs superb) and bring it over to your place for a quick experiment. It's an OEM Holley replacement carb that worked absolutely perfect right out of the box.
Any day after work is fine with me - I typically get off at 3PM. FYI - Won't be available this Friday or the weekend since I'll be pit crewing at the Vintage races at Sears Point.
Let me know if I can be of help.... Charlie