The vacuum modulator diaphram can have a small hole in it and still function more or less correctly. If it has a large enough hole to not respond to engine vacuum, it would be sucking up the tranny fluid fairly quickly, enough to notice within a few days (in my experience). Take Sixstarved's advice and pull the vacuum line off at the tranny and check for fluid. This will either confirm it or eliminate this as a possible problem.
The tranny will shift at a much higher rpm with the vacuum line disconnected (not as high as full throttle, but still high and hard) so make sure you have it back on correctly.
As far as the timing goes, another check would be to wait until your tank is almost empty, then put in half a tank of the next lower grade fuel. If it doesn't start pinging after about an hour of driving, you may need more timing. At my altitude (3200') I can usually run 9.5-10:1 on mid-grade fuel. This tuning of carbs and distributors is one of my tasks at work, and I usually have to fix what the other "performance" shops have done, so I can walk you through the whole thing if you want (as can several others here). "Why suffer through long acceleration when you can lessen your misery....."